From: Sebastián Ramírez <tiangolo@gmail.com>
Date: Sun, 28 Jun 2020 18:13:30 +0000 (+0200)
Subject: 📝 Use Optional in docs (#1644)
X-Git-Tag: 0.58.1~13
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1f01ce9615fe83ea5235820266e3a78ae8768847;p=thirdparty%2Ffastapi%2Ffastapi.git

📝 Use Optional in docs (#1644)

* Updated .py files with Optional tag (up to body_nested_models)

* Update optionals

* docs_src/ all updates, few I was unsure of

* Updated markdown files with Optional param

* es: Add Optional typing to index.md

* Last of markdown files updated with Optional param

* Update highlight lines

* it: Add Optional typings

* README.md: Update with Optional typings

* Update more highlight increments

* Update highlights

* schema-extra-example.md: Update highlights

* updating highlighting on website to reflect .py changes

* Update highlighting for query-params & response-directly

* Address PR comments

* Get rid of unnecessary comment

* ⏪ Revert Optional in Chinese docs as it probably also requires changes in text

* 🎨 Apply format

* ⏪ Revert modified example

* ♻️ Simplify example in docs

* 📝 Update OpenAPI callback example to use Optional

* ✨ Add Optional types to tests

* 📝 Update docs about query params, default to using Optional

* 🎨 Update code examples line highlighting

* 📝 Update nested models docs to use "type parameters" instead of "subtypes"

* 📝 Add notes about FastAPI usage of None

including:

= None

and

= Query(None)

and clarify relationship with Optional[str]

* 📝 Add note about response_model_by_alias

* ♻️ Simplify query param list example

* 🔥 Remove test for removed example

* ✅ Update test for updated example

Co-authored-by: Christopher Nguyen <chrisngyn99@gmail.com>
Co-authored-by: yk396 <yk396@cornell.edu>
Co-authored-by: Kai Chen <kaichen120@gmail.com>
---

diff --git a/README.md b/README.md
index b74421fa9d..4c863c71fa 100644
--- a/README.md
+++ b/README.md
@@ -131,6 +131,8 @@ $ pip install uvicorn
 * Create a file `main.py` with:
 
 ```Python
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -142,7 +144,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -151,7 +153,9 @@ def read_item(item_id: int, q: str = None):
 
 If your code uses `async` / `await`, use `async def`:
 
-```Python hl_lines="7 12"
+```Python hl_lines="9 14"
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -163,7 +167,7 @@ async def read_root():
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: int, q: str = None):
+async def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -241,7 +245,9 @@ Now modify the file `main.py` to receive a body from a `PUT` request.
 
 Declare the body using standard Python types, thanks to Pydantic.
 
-```Python hl_lines="2  7 8 9 10  23 24 25"
+```Python hl_lines="4  9 10 11 12  25 26 27"
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -251,7 +257,7 @@ app = FastAPI()
 class Item(BaseModel):
     name: str
     price: float
-    is_offer: bool = None
+    is_offer: Optional[bool] = None
 
 
 @app.get("/")
@@ -260,7 +266,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 
 
diff --git a/docs/en/docs/advanced/additional-responses.md b/docs/en/docs/advanced/additional-responses.md
index 4b2abaada3..c8d443c3ca 100644
--- a/docs/en/docs/advanced/additional-responses.md
+++ b/docs/en/docs/advanced/additional-responses.md
@@ -168,7 +168,7 @@ You can use this same `responses` parameter to add different media types for the
 
 For example, you can add an additional media type of `image/png`, declaring that your *path operation* can return a JSON object (with media type `application/json`) or a PNG image:
 
-```Python hl_lines="17 18 19 20 21 22 23 24 28"
+```Python hl_lines="19 20 21 22 23 24  28"
 {!../../../docs_src/additional_responses/tutorial002.py!}
 ```
 
@@ -228,7 +228,7 @@ You can use that technique to re-use some predefined responses in your *path ope
 
 For example:
 
-```Python hl_lines="11 12 13 14 15 24"
+```Python hl_lines="13 14 15 16 17 26"
 {!../../../docs_src/additional_responses/tutorial004.py!}
 ```
 
diff --git a/docs/en/docs/advanced/additional-status-codes.md b/docs/en/docs/advanced/additional-status-codes.md
index b9a32cfa3b..eb6031953a 100644
--- a/docs/en/docs/advanced/additional-status-codes.md
+++ b/docs/en/docs/advanced/additional-status-codes.md
@@ -14,7 +14,7 @@ But you also want it to accept new items. And when the items didn't exist before
 
 To achieve that, import `JSONResponse`, and return your content there directly, setting the `status_code` that you want:
 
-```Python hl_lines="2  19"
+```Python hl_lines="4  23"
 {!../../../docs_src/additional_status_codes/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/advanced/openapi-callbacks.md b/docs/en/docs/advanced/openapi-callbacks.md
index 15c0ba2a1d..4c3d97e385 100644
--- a/docs/en/docs/advanced/openapi-callbacks.md
+++ b/docs/en/docs/advanced/openapi-callbacks.md
@@ -31,7 +31,7 @@ It will have a *path operation* that will receive an `Invoice` body, and a query
 
 This part is pretty normal, most of the code is probably already familiar to you:
 
-```Python hl_lines="8 9 10 11 12  34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53"
+```Python hl_lines="10 11 12 13 14  37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54"
 {!../../../docs_src/openapi_callbacks/tutorial001.py!}
 ```
 
@@ -92,7 +92,7 @@ Because of that, you need to declare what will be the `default_response_class`,
 
     But as we are never calling `app.include_router(some_router)`, we need to set the `default_response_class` during creation of the `APIRouter`.
 
-```Python hl_lines="3 24"
+```Python hl_lines="5 26"
 {!../../../docs_src/openapi_callbacks/tutorial001.py!}
 ```
 
@@ -105,7 +105,7 @@ It should look just like a normal FastAPI *path operation*:
 * It should probably have a declaration of the body it should receive, e.g. `body: InvoiceEvent`.
 * And it could also have a declaration of the response it should return, e.g. `response_model=InvoiceEventReceived`.
 
-```Python hl_lines="15 16 17  20 21  27 28 29 30 31"
+```Python hl_lines="17 18 19  22 23  29 30 31 32 33"
 {!../../../docs_src/openapi_callbacks/tutorial001.py!}
 ```
 
@@ -172,7 +172,7 @@ At this point you have the *callback path operation(s)* needed (the one(s) that
 
 Now use the parameter `callbacks` in *your API's path operation decorator* to pass the attribute `.routes` (that's actually just a `list` of routes/*path operations*) from that callback router:
 
-```Python hl_lines="34"
+```Python hl_lines="36"
 {!../../../docs_src/openapi_callbacks/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/advanced/response-directly.md b/docs/en/docs/advanced/response-directly.md
index f1dca1812b..f0ab2831d5 100644
--- a/docs/en/docs/advanced/response-directly.md
+++ b/docs/en/docs/advanced/response-directly.md
@@ -31,7 +31,7 @@ For example, you cannot put a Pydantic model in a `JSONResponse` without first c
 
 For those cases, you can use the `jsonable_encoder` to convert your data before passing it to a response:
 
-```Python hl_lines="4 6 20 21"
+```Python hl_lines="6 7  21 22"
 {!../../../docs_src/response_directly/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/advanced/testing-dependencies.md b/docs/en/docs/advanced/testing-dependencies.md
index f2c283947f..0dc20afff9 100644
--- a/docs/en/docs/advanced/testing-dependencies.md
+++ b/docs/en/docs/advanced/testing-dependencies.md
@@ -28,7 +28,7 @@ To override a dependency for testing, you put as a key the original dependency (
 
 And then **FastAPI** will call that override instead of the original dependency.
 
-```Python hl_lines="24 25 28"
+```Python hl_lines="26 27 30"
 {!../../../docs_src/dependency_testing/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/advanced/websockets.md b/docs/en/docs/advanced/websockets.md
index 6cacc2e6f3..083c75752a 100644
--- a/docs/en/docs/advanced/websockets.md
+++ b/docs/en/docs/advanced/websockets.md
@@ -98,7 +98,7 @@ In WebSocket endpoints you can import from `fastapi` and use:
 
 They work the same way as for other FastAPI endpoints/*path operations*:
 
-```Python hl_lines="56 57 58 59 60 61  64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79"
+```Python hl_lines="58 59 60 61 62 63 64 65  68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83"
 {!../../../docs_src/websockets/tutorial002.py!}
 ```
 
diff --git a/docs/en/docs/deployment.md b/docs/en/docs/deployment.md
index 94ab1b90b9..5e62d1e8d5 100644
--- a/docs/en/docs/deployment.md
+++ b/docs/en/docs/deployment.md
@@ -161,6 +161,8 @@ CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "80"]
 * Create a `main.py` file with:
 
 ```Python
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -172,7 +174,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
diff --git a/docs/en/docs/index.md b/docs/en/docs/index.md
index b74421fa9d..4c863c71fa 100644
--- a/docs/en/docs/index.md
+++ b/docs/en/docs/index.md
@@ -131,6 +131,8 @@ $ pip install uvicorn
 * Create a file `main.py` with:
 
 ```Python
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -142,7 +144,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -151,7 +153,9 @@ def read_item(item_id: int, q: str = None):
 
 If your code uses `async` / `await`, use `async def`:
 
-```Python hl_lines="7 12"
+```Python hl_lines="9 14"
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -163,7 +167,7 @@ async def read_root():
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: int, q: str = None):
+async def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -241,7 +245,9 @@ Now modify the file `main.py` to receive a body from a `PUT` request.
 
 Declare the body using standard Python types, thanks to Pydantic.
 
-```Python hl_lines="2  7 8 9 10  23 24 25"
+```Python hl_lines="4  9 10 11 12  25 26 27"
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -251,7 +257,7 @@ app = FastAPI()
 class Item(BaseModel):
     name: str
     price: float
-    is_offer: bool = None
+    is_offer: Optional[bool] = None
 
 
 @app.get("/")
@@ -260,7 +266,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 
 
diff --git a/docs/en/docs/tutorial/background-tasks.md b/docs/en/docs/tutorial/background-tasks.md
index 3771eff712..7ee8d8a78e 100644
--- a/docs/en/docs/tutorial/background-tasks.md
+++ b/docs/en/docs/tutorial/background-tasks.md
@@ -57,7 +57,7 @@ Using `BackgroundTasks` also works with the dependency injection system, you can
 
 **FastAPI** knows what to do in each case and how to re-use the same object, so that all the background tasks are merged together and are run in the background afterwards:
 
-```Python hl_lines="11 14 20 23"
+```Python hl_lines="13 15 22 25"
 {!../../../docs_src/background_tasks/tutorial002.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/body-fields.md b/docs/en/docs/tutorial/body-fields.md
index 91e6b1a101..444b901450 100644
--- a/docs/en/docs/tutorial/body-fields.md
+++ b/docs/en/docs/tutorial/body-fields.md
@@ -6,7 +6,7 @@ The same way you can declare additional validation and metadata in *path operati
 
 First, you have to import it:
 
-```Python hl_lines="2"
+```Python hl_lines="4"
 {!../../../docs_src/body_fields/tutorial001.py!}
 ```
 
@@ -17,7 +17,7 @@ First, you have to import it:
 
 You can then use `Field` with model attributes:
 
-```Python hl_lines="9 10"
+```Python hl_lines="11 12 13 14"
 {!../../../docs_src/body_fields/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/body-multiple-params.md b/docs/en/docs/tutorial/body-multiple-params.md
index 6d5e6e39de..48883e4cda 100644
--- a/docs/en/docs/tutorial/body-multiple-params.md
+++ b/docs/en/docs/tutorial/body-multiple-params.md
@@ -8,7 +8,7 @@ First, of course, you can mix `Path`, `Query` and request body parameter declara
 
 And you can also declare body parameters as optional, by setting the default to `None`:
 
-```Python hl_lines="17 18 19"
+```Python hl_lines="19 20 21"
 {!../../../docs_src/body_multiple_params/tutorial001.py!}
 ```
 
@@ -30,7 +30,7 @@ In the previous example, the *path operations* would expect a JSON body with the
 
 But you can also declare multiple body parameters, e.g. `item` and `user`:
 
-```Python hl_lines="20"
+```Python hl_lines="22"
 {!../../../docs_src/body_multiple_params/tutorial002.py!}
 ```
 
@@ -72,7 +72,7 @@ If you declare it as is, because it is a singular value, **FastAPI** will assume
 But you can instruct **FastAPI** to treat it as another body key using `Body`:
 
 
-```Python hl_lines="21"
+```Python hl_lines="23"
 {!../../../docs_src/body_multiple_params/tutorial003.py!}
 ```
 
@@ -104,12 +104,12 @@ Of course, you can also declare additional query parameters whenever you need, a
 As, by default, singular values are interpreted as query parameters, you don't have to explicitly add a `Query`, you can just do:
 
 ```Python
-q: str = None
+q: Optional[str] = None
 ```
 
 as in:
 
-```Python hl_lines="25"
+```Python hl_lines="27"
 {!../../../docs_src/body_multiple_params/tutorial004.py!}
 ```
 
@@ -131,7 +131,7 @@ item: Item = Body(..., embed=True)
 
 as in:
 
-```Python hl_lines="15"
+```Python hl_lines="17"
 {!../../../docs_src/body_multiple_params/tutorial005.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/body-nested-models.md b/docs/en/docs/tutorial/body-nested-models.md
index 993389c903..987de42a84 100644
--- a/docs/en/docs/tutorial/body-nested-models.md
+++ b/docs/en/docs/tutorial/body-nested-models.md
@@ -6,15 +6,15 @@ With **FastAPI**, you can define, validate, document, and use arbitrarily deeply
 
 You can define an attribute to be a subtype. For example, a Python `list`:
 
-```Python hl_lines="12"
+```Python hl_lines="14"
 {!../../../docs_src/body_nested_models/tutorial001.py!}
 ```
 
 This will make `tags` be a list of items. Although it doesn't declare the type of each of the items.
 
-## List fields with subtype
+## List fields with type parameter
 
-But Python has a specific way to declare lists with subtypes:
+But Python has a specific way to declare lists with internal types, or "type parameters":
 
 ### Import typing's `List`
 
@@ -24,12 +24,12 @@ First, import `List` from standard Python's `typing` module:
 {!../../../docs_src/body_nested_models/tutorial002.py!}
 ```
 
-### Declare a `List` with a subtype
+### Declare a `List` with a type parameter
 
-To declare types that have subtypes, like `list`, `dict`, `tuple`:
+To declare types that have type parameters (internal types), like `list`, `dict`, `tuple`:
 
 * Import them from the `typing` module
-* Pass the subtype(s) as "type arguments" using square brackets: `[` and `]`
+* Pass the internal type(s) as "type parameters" using square brackets: `[` and `]`
 
 ```Python
 from typing import List
@@ -39,7 +39,7 @@ my_list: List[str]
 
 That's all standard Python syntax for type declarations.
 
-Use that same standard syntax for model attributes with subtypes.
+Use that same standard syntax for model attributes with internal types.
 
 So, in our example, we can make `tags` be specifically a "list of strings":
 
@@ -71,7 +71,7 @@ Each attribute of a Pydantic model has a type.
 
 But that type can itself be another Pydantic model.
 
-So, you can declare deeply nested JSON `object`s with specific attribute names, types and validations.
+So, you can declare deeply nested JSON "objects" with specific attribute names, types and validations.
 
 All that, arbitrarily nested.
 
@@ -174,7 +174,7 @@ You can define arbitrarily deeply nested models:
 ```
 
 !!! info
-    Notice how `Offer` as a list of `Item`s, which in turn have an optional list of `Image`s
+    Notice how `Offer` has a list of `Item`s, which in turn have an optional list of `Image`s
 
 ## Bodies of pure lists
 
diff --git a/docs/en/docs/tutorial/body.md b/docs/en/docs/tutorial/body.md
index b2cde0762c..baa013809e 100644
--- a/docs/en/docs/tutorial/body.md
+++ b/docs/en/docs/tutorial/body.md
@@ -17,7 +17,7 @@ To declare a **request** body, you use <a href="https://pydantic-docs.helpmanual
 
 First, you need to import `BaseModel` from `pydantic`:
 
-```Python hl_lines="2"
+```Python hl_lines="4"
 {!../../../docs_src/body/tutorial001.py!}
 ```
 
@@ -27,7 +27,7 @@ Then you declare your data model as a class that inherits from `BaseModel`.
 
 Use standard Python types for all the attributes:
 
-```Python hl_lines="5 6 7 8 9"
+```Python hl_lines="7 8 9 10 11"
 {!../../../docs_src/body/tutorial001.py!}
 ```
 
@@ -57,7 +57,7 @@ For example, this model above declares a JSON "`object`" (or Python `dict`) like
 
 To add it to your *path operation*, declare it the same way you declared path and query parameters:
 
-```Python hl_lines="16"
+```Python hl_lines="18"
 {!../../../docs_src/body/tutorial001.py!}
 ```
 
@@ -123,7 +123,7 @@ But you would get the same editor support with <a href="https://www.jetbrains.co
 
 Inside of the function, you can access all the attributes of the model object directly:
 
-```Python hl_lines="19"
+```Python hl_lines="21"
 {!../../../docs_src/body/tutorial002.py!}
 ```
 
@@ -133,7 +133,7 @@ You can declare path parameters and body requests at the same time.
 
 **FastAPI** will recognize that the function parameters that match path parameters should be **taken from the path**, and that function parameters that are declared to be Pydantic models should be **taken from the request body**.
 
-```Python hl_lines="15 16"
+```Python hl_lines="17 18"
 {!../../../docs_src/body/tutorial003.py!}
 ```
 
@@ -143,7 +143,7 @@ You can also declare **body**, **path** and **query** parameters, all at the sam
 
 **FastAPI** will recognize each of them and take the data from the correct place.
 
-```Python hl_lines="16"
+```Python hl_lines="18"
 {!../../../docs_src/body/tutorial004.py!}
 ```
 
@@ -153,6 +153,11 @@ The function parameters will be recognized as follows:
 * If the parameter is of a **singular type** (like `int`, `float`, `str`, `bool`, etc) it will be interpreted as a **query** parameter.
 * If the parameter is declared to be of the type of a **Pydantic model**, it will be interpreted as a request **body**.
 
+!!! note
+    FastAPI will know that the value of `q` is not required because of the default value `= None`.
+
+    The `Optional` in `Optional[str]` is not used by FastAPI, but will allow your editor to give you better support and detect errors.
+
 ## Without Pydantic
 
 If you don't want to use Pydantic models, you can also use **Body** parameters. See the docs for [Body - Multiple Parameters: Singular values in body](body-multiple-params.md#singular-values-in-body){.internal-link target=_blank}.
diff --git a/docs/en/docs/tutorial/cookie-params.md b/docs/en/docs/tutorial/cookie-params.md
index 658c52c464..9aa2300c4b 100644
--- a/docs/en/docs/tutorial/cookie-params.md
+++ b/docs/en/docs/tutorial/cookie-params.md
@@ -6,7 +6,7 @@ You can define Cookie parameters the same way you define `Query` and `Path` para
 
 First import `Cookie`:
 
-```Python hl_lines="1"
+```Python hl_lines="3"
 {!../../../docs_src/cookie_params/tutorial001.py!}
 ```
 
@@ -16,7 +16,7 @@ Then declare the cookie parameters using the same structure as with `Path` and `
 
 The first value is the default value, you can pass all the extra validation or annotation parameters:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/cookie_params/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/dependencies/classes-as-dependencies.md b/docs/en/docs/tutorial/dependencies/classes-as-dependencies.md
index b4d78af84e..3ae184d955 100644
--- a/docs/en/docs/tutorial/dependencies/classes-as-dependencies.md
+++ b/docs/en/docs/tutorial/dependencies/classes-as-dependencies.md
@@ -6,7 +6,7 @@ Before diving deeper into the **Dependency Injection** system, let's upgrade the
 
 In the previous example, we were returning a `dict` from our dependency ("dependable"):
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/dependencies/tutorial001.py!}
 ```
 
@@ -71,19 +71,19 @@ That also applies to callables with no parameters at all. The same as it would b
 
 Then, we can change the dependency "dependable" `common_parameters` from above to the class `CommonQueryParameters`:
 
-```Python hl_lines="9 10 11 12 13"
+```Python hl_lines="11 12 13 14 15"
 {!../../../docs_src/dependencies/tutorial002.py!}
 ```
 
 Pay attention to the `__init__` method used to create the instance of the class:
 
-```Python hl_lines="10"
+```Python hl_lines="12"
 {!../../../docs_src/dependencies/tutorial002.py!}
 ```
 
 ...it has the same parameters as our previous `common_parameters`:
 
-```Python hl_lines="6"
+```Python hl_lines="8"
 {!../../../docs_src/dependencies/tutorial001.py!}
 ```
 
@@ -103,7 +103,7 @@ Now you can declare your dependency using this class.
 
 And as when **FastAPI** calls that class the value that will be passed as `commons` to your function will be an "instance" of the class, you can declare that parameter `commons` to be of type of the class, `CommonQueryParams`.
 
-```Python hl_lines="17"
+```Python hl_lines="19"
 {!../../../docs_src/dependencies/tutorial002.py!}
 ```
 
@@ -143,7 +143,7 @@ commons = Depends(CommonQueryParams)
 
 ..as in:
 
-```Python hl_lines="17"
+```Python hl_lines="19"
 {!../../../docs_src/dependencies/tutorial003.py!}
 ```
 
@@ -179,7 +179,7 @@ So, you can declare the dependency as the type of the variable, and use `Depends
 
 So, the same example would look like:
 
-```Python hl_lines="17"
+```Python hl_lines="19"
 {!../../../docs_src/dependencies/tutorial004.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/dependencies/index.md b/docs/en/docs/tutorial/dependencies/index.md
index 5b8d11ea76..1b86e16791 100644
--- a/docs/en/docs/tutorial/dependencies/index.md
+++ b/docs/en/docs/tutorial/dependencies/index.md
@@ -31,7 +31,7 @@ Let's first focus on the dependency.
 
 It is just a function that can take all the same parameters that a *path operation function* can take:
 
-```Python hl_lines="6 7"
+```Python hl_lines="8 9"
 {!../../../docs_src/dependencies/tutorial001.py!}
 ```
 
@@ -55,7 +55,7 @@ And then it just returns a `dict` containing those values.
 
 ### Import `Depends`
 
-```Python hl_lines="1"
+```Python hl_lines="3"
 {!../../../docs_src/dependencies/tutorial001.py!}
 ```
 
@@ -63,7 +63,7 @@ And then it just returns a `dict` containing those values.
 
 The same way you use `Body`, `Query`, etc. with your *path operation function* parameters, use `Depends` with a new parameter:
 
-```Python hl_lines="11 16"
+```Python hl_lines="13  18"
 {!../../../docs_src/dependencies/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/dependencies/sub-dependencies.md b/docs/en/docs/tutorial/dependencies/sub-dependencies.md
index 71b1404d6f..3ecccebaf7 100644
--- a/docs/en/docs/tutorial/dependencies/sub-dependencies.md
+++ b/docs/en/docs/tutorial/dependencies/sub-dependencies.md
@@ -10,7 +10,7 @@ They can be as **deep** as you need them to be.
 
 You could create a first dependency ("dependable") like:
 
-```Python hl_lines="6 7"
+```Python hl_lines="8 9"
 {!../../../docs_src/dependencies/tutorial005.py!}
 ```
 
@@ -22,7 +22,7 @@ This is quite simple (not very useful), but will help us focus on how the sub-de
 
 Then you can create another dependency function (a "dependable") that at the same time declares a dependency of its own (so it is a "dependant" too):
 
-```Python hl_lines="11"
+```Python hl_lines="13"
 {!../../../docs_src/dependencies/tutorial005.py!}
 ```
 
@@ -37,7 +37,7 @@ Let's focus on the parameters declared:
 
 Then we can use the dependency with:
 
-```Python hl_lines="19"
+```Python hl_lines="21"
 {!../../../docs_src/dependencies/tutorial005.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/encoder.md b/docs/en/docs/tutorial/encoder.md
index 3879f976af..d1d59c43ce 100644
--- a/docs/en/docs/tutorial/encoder.md
+++ b/docs/en/docs/tutorial/encoder.md
@@ -20,7 +20,7 @@ You can use `jsonable_encoder` for that.
 
 It receives an object, like a Pydantic model, and returns a JSON compatible version:
 
-```Python hl_lines="4 21"
+```Python hl_lines="5 22"
 {!../../../docs_src/encoder/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/extra-data-types.md b/docs/en/docs/tutorial/extra-data-types.md
index 07c1ed06f7..46ebc4b61b 100644
--- a/docs/en/docs/tutorial/extra-data-types.md
+++ b/docs/en/docs/tutorial/extra-data-types.md
@@ -54,12 +54,12 @@ Here are some of the additional data types you can use:
 
 Here's an example *path operation* with parameters using some of the above types.
 
-```Python hl_lines="1 2 11 12 13 14 15"
+```Python hl_lines="1  3  12 13 14 15 16"
 {!../../../docs_src/extra_data_types/tutorial001.py!}
 ```
 
 Note that the parameters inside the function have their natural data type, and you can, for example, perform normal date manipulations, like:
 
-```Python hl_lines="17 18"
+```Python hl_lines="18 19"
 {!../../../docs_src/extra_data_types/tutorial001.py!}
 ```
diff --git a/docs/en/docs/tutorial/extra-models.md b/docs/en/docs/tutorial/extra-models.md
index 5b8bf5a2b8..67d4ec4730 100644
--- a/docs/en/docs/tutorial/extra-models.md
+++ b/docs/en/docs/tutorial/extra-models.md
@@ -17,7 +17,7 @@ This is especially the case for user models, because:
 
 Here's a general idea of how the models could look like with their password fields and the places where they are used:
 
-```Python hl_lines="7 9  14   20 22  27 28  31 32 33  38 39"
+```Python hl_lines="9 11 16 22 24  29 30  33 34 35  40 41"
 {!../../../docs_src/extra_models/tutorial001.py!}
 ```
 
@@ -150,7 +150,7 @@ All the data conversion, validation, documentation, etc. will still work as norm
 
 That way, we can declare just the differences between the models (with plaintext `password`, with `hashed_password` and without password):
 
-```Python hl_lines="7  13 14  17 18  21 22"
+```Python hl_lines="9  15 16  19 20  23 24"
 {!../../../docs_src/extra_models/tutorial002.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/handling-errors.md b/docs/en/docs/tutorial/handling-errors.md
index c5d36702ce..c2a130a127 100644
--- a/docs/en/docs/tutorial/handling-errors.md
+++ b/docs/en/docs/tutorial/handling-errors.md
@@ -209,7 +209,7 @@ Now try sending an invalid item like:
 
 You will receive a response telling you that the data is invalid containing the received body:
 
-```JSON hl_lines="13 14 15 16"
+```JSON hl_lines="12 13 14 15"
 {
   "detail": [
     {
diff --git a/docs/en/docs/tutorial/header-params.md b/docs/en/docs/tutorial/header-params.md
index 738d2a559e..57570153ff 100644
--- a/docs/en/docs/tutorial/header-params.md
+++ b/docs/en/docs/tutorial/header-params.md
@@ -6,7 +6,7 @@ You can define Header parameters the same way you define `Query`, `Path` and `Co
 
 First import `Header`:
 
-```Python hl_lines="1"
+```Python hl_lines="3"
 {!../../../docs_src/header_params/tutorial001.py!}
 ```
 
@@ -16,7 +16,7 @@ Then declare the header parameters using the same structure as with `Path`, `Que
 
 The first value is the default value, you can pass all the extra validation or annotation parameters:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/header_params/tutorial001.py!}
 ```
 
@@ -44,7 +44,7 @@ So, you can use `user_agent` as you normally would in Python code, instead of ne
 
 If for some reason you need to disable automatic conversion of underscores to hyphens, set the parameter `convert_underscores` of `Header` to `False`:
 
-```Python hl_lines="7"
+```Python hl_lines="10"
 {!../../../docs_src/header_params/tutorial002.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/path-params-numeric-validations.md b/docs/en/docs/tutorial/path-params-numeric-validations.md
index 9ae4c8b1a4..1fcd9dbdbc 100644
--- a/docs/en/docs/tutorial/path-params-numeric-validations.md
+++ b/docs/en/docs/tutorial/path-params-numeric-validations.md
@@ -6,7 +6,7 @@ The same way you can declare more validations and metadata for query parameters
 
 First, import `Path` from `fastapi`:
 
-```Python hl_lines="1"
+```Python hl_lines="3"
 {!../../../docs_src/path_params_numeric_validations/tutorial001.py!}
 ```
 
@@ -16,7 +16,7 @@ You can declare all the same parameters as for `Query`.
 
 For example, to declare a `title` metadata value for the path parameter `item_id` you can type:
 
-```Python hl_lines="8"
+```Python hl_lines="10"
 {!../../../docs_src/path_params_numeric_validations/tutorial001.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/query-params-str-validations.md b/docs/en/docs/tutorial/query-params-str-validations.md
index abde56df4b..465ce3f88e 100644
--- a/docs/en/docs/tutorial/query-params-str-validations.md
+++ b/docs/en/docs/tutorial/query-params-str-validations.md
@@ -4,11 +4,16 @@
 
 Let's take this application as example:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/query_params_str_validations/tutorial001.py!}
 ```
 
-The query parameter `q` is of type `str`, and by default is `None`, so it is optional.
+The query parameter `q` is of type `Optional[str]`, that means that it's of type `str` but could also be `None`, and indeed, the default value is `None`, so FastAPI will know it's not required.
+
+!!! note
+    FastAPI will know that the value of `q` is not required because of the default value `= None`.
+
+    The `Optional` in `Optional[str]` is not used by FastAPI, but will allow your editor to give you better support and detect errors.
 
 ## Additional validation
 
@@ -18,7 +23,7 @@ We are going to enforce that even though `q` is optional, whenever it is provide
 
 To achieve that, first import `Query` from `fastapi`:
 
-```Python hl_lines="1"
+```Python hl_lines="3"
 {!../../../docs_src/query_params_str_validations/tutorial002.py!}
 ```
 
@@ -26,7 +31,7 @@ To achieve that, first import `Query` from `fastapi`:
 
 And now use it as the default value of your parameter, setting the parameter `max_length` to 50:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/query_params_str_validations/tutorial002.py!}
 ```
 
@@ -35,18 +40,35 @@ As we have to replace the default value `None` with `Query(None)`, the first par
 So:
 
 ```Python
-q: str = Query(None)
+q: Optional[str] = Query(None)
 ```
 
 ...makes the parameter optional, the same as:
 
 ```Python
-q: str = None
+q: Optional[str] = None
 ```
 
 But it declares it explicitly as being a query parameter.
 
-And then, we can pass more parameters to `Query`. In this case, the `max_length` parameter that applies to strings:
+!!! info
+    Have in mind that FastAPI cares about the part:
+
+    ```Python
+    = None
+    ```
+
+    or the:
+
+    ```Python
+    = Query(None)
+    ```
+
+    and will use that `None` to detect that the query parameter is not required.
+
+    The `Optional` part is only to allow your editor to provide better support.
+
+Then, we can pass more parameters to `Query`. In this case, the `max_length` parameter that applies to strings:
 
 ```Python
 q: str = Query(None, max_length=50)
@@ -58,7 +80,7 @@ This will validate the data, show a clear error when the data is not valid, and
 
 You can also add a parameter `min_length`:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/query_params_str_validations/tutorial003.py!}
 ```
 
@@ -66,7 +88,7 @@ You can also add a parameter `min_length`:
 
 You can define a <abbr title="A regular expression, regex or regexp is a sequence of characters that define a search pattern for strings.">regular expression</abbr> that the parameter should match:
 
-```Python hl_lines="8"
+```Python hl_lines="10"
 {!../../../docs_src/query_params_str_validations/tutorial004.py!}
 ```
 
@@ -104,13 +126,13 @@ q: str
 instead of:
 
 ```Python
-q: str = None
+q: Optional[str] = None
 ```
 
 But we are now declaring it with `Query`, for example like:
 
 ```Python
-q: str = Query(None, min_length=3)
+q: Optional[str] = Query(None, min_length=3)
 ```
 
 So, when you need to declare a value as required while using `Query`, you can use `...` as the first argument:
@@ -211,13 +233,13 @@ That information will be included in the generated OpenAPI and used by the docum
 
 You can add a `title`:
 
-```Python hl_lines="7"
+```Python hl_lines="10"
 {!../../../docs_src/query_params_str_validations/tutorial007.py!}
 ```
 
 And a `description`:
 
-```Python hl_lines="11"
+```Python hl_lines="13"
 {!../../../docs_src/query_params_str_validations/tutorial008.py!}
 ```
 
@@ -239,7 +261,7 @@ But you still need it to be exactly `item-query`...
 
 Then you can declare an `alias`, and that alias is what will be used to find the parameter value:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/query_params_str_validations/tutorial009.py!}
 ```
 
@@ -251,7 +273,7 @@ You have to leave it there a while because there are clients using it, but you w
 
 Then pass the parameter `deprecated=True` to `Query`:
 
-```Python hl_lines="16"
+```Python hl_lines="18"
 {!../../../docs_src/query_params_str_validations/tutorial010.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/query-params.md b/docs/en/docs/tutorial/query-params.md
index 0efc57e1b8..d5dec36def 100644
--- a/docs/en/docs/tutorial/query-params.md
+++ b/docs/en/docs/tutorial/query-params.md
@@ -63,7 +63,7 @@ The parameter values in your function will be:
 
 The same way, you can declare optional query parameters, by setting their default to `None`:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/query_params/tutorial002.py!}
 ```
 
@@ -72,11 +72,16 @@ In this case, the function parameter `q` will be optional, and will be `None` by
 !!! check
     Also notice that **FastAPI** is smart enough to notice that the path parameter `item_id` is a path parameter and `q` is not, so, it's a query parameter.
 
+!!! note
+    FastAPI will know that `q` is optional because of the `= None`.
+
+    The `Optional` in `Optional[str]` is not used by FastAPI (FastAPI will only use the `str` part), but the `Optional[str]` will let your editor help you finding errors in your code.
+
 ## Query parameter type conversion
 
 You can also declare `bool` types, and they will be converted:
 
-```Python hl_lines="7"
+```Python hl_lines="9"
 {!../../../docs_src/query_params/tutorial003.py!}
 ```
 
@@ -121,7 +126,7 @@ And you don't have to declare them in any specific order.
 
 They will be detected by name:
 
-```Python hl_lines="6 8"
+```Python hl_lines="8 10"
 {!../../../docs_src/query_params/tutorial004.py!}
 ```
 
@@ -179,7 +184,7 @@ http://127.0.0.1:8000/items/foo-item?needy=sooooneedy
 
 And of course, you can define some parameters as required, some as having a default value, and some entirely optional:
 
-```Python hl_lines="7"
+```Python hl_lines="10"
 {!../../../docs_src/query_params/tutorial006.py!}
 ```
 
@@ -191,36 +196,3 @@ In this case, there are 3 query parameters:
 
 !!! tip
     You could also use `Enum`s the same way as with [Path Parameters](path-params.md#predefined-values){.internal-link target=_blank}.
-
-## Optional type declarations
-
-!!! warning
-    This might be an advanced use case.
-
-    You might want to skip it.
-
-If you are using `mypy` it could complain with type declarations like:
-
-```Python
-limit: int = None
-```
-
-With an error like:
-
-```
-Incompatible types in assignment (expression has type "None", variable has type "int")
-```
-
-In those cases you can use `Optional` to tell `mypy` that the value could be `None`, like:
-
-```Python
-from typing import Optional
-
-limit: Optional[int] = None
-```
-
-In a *path operation* that could look like:
-
-```Python hl_lines="9"
-{!../../../docs_src/query_params/tutorial007.py!}
-```
diff --git a/docs/en/docs/tutorial/response-model.md b/docs/en/docs/tutorial/response-model.md
index dd76eca6ef..b7201ee77d 100644
--- a/docs/en/docs/tutorial/response-model.md
+++ b/docs/en/docs/tutorial/response-model.md
@@ -35,13 +35,13 @@ But most importantly:
 
 Here we are declaring a `UserIn` model, it will contain a plaintext password:
 
-```Python hl_lines="7 9"
+```Python hl_lines="9 11"
 {!../../../docs_src/response_model/tutorial002.py!}
 ```
 
 And we are using this model to declare our input and the same model to declare our output:
 
-```Python hl_lines="15 16"
+```Python hl_lines="17 18"
 {!../../../docs_src/response_model/tutorial002.py!}
 ```
 
@@ -58,19 +58,19 @@ But if we use the same model for another *path operation*, we could be sending o
 
 We can instead create an input model with the plaintext password and an output model without it:
 
-```Python hl_lines="7 9 14"
+```Python hl_lines="9 11 16"
 {!../../../docs_src/response_model/tutorial003.py!}
 ```
 
 Here, even though our *path operation function* is returning the same input user that contains the password:
 
-```Python hl_lines="22"
+```Python hl_lines="24"
 {!../../../docs_src/response_model/tutorial003.py!}
 ```
 
 ...we declared the `response_model` to be our model `UserOut`, that doesn't include the password:
 
-```Python hl_lines="20"
+```Python hl_lines="22"
 {!../../../docs_src/response_model/tutorial003.py!}
 ```
 
@@ -94,9 +94,9 @@ Your response model could have default values, like:
 {!../../../docs_src/response_model/tutorial004.py!}
 ```
 
-* `description: str = None` has a default of `None`.
+* `description: Optional[str] = None` has a default of `None`.
 * `tax: float = 10.5` has a default of `10.5`.
-* `tags: List[str] = []` has a default of an empty list: `[]`.
+* `tags: List[str] = []` as a default of an empty list: `[]`.
 
 but you might want to omit them from the result if they were not actually stored.
 
@@ -183,7 +183,9 @@ This can be used as a quick shortcut if you have only one Pydantic model and wan
 
     This is because the JSON Schema generated in your app's OpenAPI (and the docs) will still be the one for the complete model, even if you use `response_model_include` or `response_model_exclude` to omit some attributes.
 
-```Python hl_lines="29 35"
+    This also applies to `response_model_by_alias` that works similarly.
+
+```Python hl_lines="31 37"
 {!../../../docs_src/response_model/tutorial005.py!}
 ```
 
@@ -196,7 +198,7 @@ This can be used as a quick shortcut if you have only one Pydantic model and wan
 
 If you forget to use a `set` and use a `list` or `tuple` instead, FastAPI will still convert it to a `set` and it will work correctly:
 
-```Python hl_lines="29 35"
+```Python hl_lines="31 37"
 {!../../../docs_src/response_model/tutorial006.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/schema-extra-example.md b/docs/en/docs/tutorial/schema-extra-example.md
index 8a497ccd54..d0f1b843e5 100644
--- a/docs/en/docs/tutorial/schema-extra-example.md
+++ b/docs/en/docs/tutorial/schema-extra-example.md
@@ -10,7 +10,7 @@ There are several ways you can declare extra JSON Schema information.
 
 You can declare an example for a Pydantic model using `Config` and `schema_extra`, as described in <a href="https://pydantic-docs.helpmanual.io/usage/schema/#schema-customization" class="external-link" target="_blank">Pydantic's docs: Schema customization</a>:
 
-```Python hl_lines="13 14 15 16 17 18 19 20 21"
+```Python hl_lines="15 16 17 18 19 20 21 22 23"
 {!../../../docs_src/schema_extra_example/tutorial001.py!}
 ```
 
@@ -20,7 +20,7 @@ That extra info will be added as-is to the output JSON Schema.
 
 In `Field`, `Path`, `Query`, `Body` and others you'll see later, you can also declare extra info for the JSON Schema by passing any other arbitrary arguments to the function, for example, to add an `example`:
 
-```Python hl_lines="2 8 9 10 11"
+```Python hl_lines="4 10 11 12 13"
 {!../../../docs_src/schema_extra_example/tutorial002.py!}
 ```
 
@@ -33,7 +33,7 @@ The same way you can pass extra info to `Field`, you can do the same with `Path`
 
 For example, you can pass an `example` for a body request to `Body`:
 
-```Python hl_lines="19 20 21 22 23 24"
+```Python hl_lines="21 22 23 24 25 26"
 {!../../../docs_src/schema_extra_example/tutorial003.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/security/oauth2-jwt.md b/docs/en/docs/tutorial/security/oauth2-jwt.md
index 18b4e0e300..b1147cb4c5 100644
--- a/docs/en/docs/tutorial/security/oauth2-jwt.md
+++ b/docs/en/docs/tutorial/security/oauth2-jwt.md
@@ -100,7 +100,7 @@ And another utility to verify if a received password matches the hash stored.
 
 And another one to authenticate and return a user.
 
-```Python hl_lines="7  48  55 56  59 60  69 70 71 72 73 74 75"
+```Python hl_lines="8  49  56 57  60 61  70 71 72 73 74 75 76"
 {!../../../docs_src/security/tutorial004.py!}
 ```
 
@@ -135,7 +135,7 @@ Define a Pydantic Model that will be used in the token endpoint for the response
 
 Create a utility function to generate a new access token.
 
-```Python hl_lines="3  6  12 13 14  28 29 30  78 79 80 81 82 83 84 85 86"
+```Python hl_lines="4  7  13 14 15  29 30 31  79 80 81 82 83 84 85 86 87"
 {!../../../docs_src/security/tutorial004.py!}
 ```
 
@@ -147,7 +147,7 @@ Decode the received token, verify it, and return the current user.
 
 If the token is invalid, return an HTTP error right away.
 
-```Python hl_lines="89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106"
+```Python hl_lines="90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107"
 {!../../../docs_src/security/tutorial004.py!}
 ```
 
@@ -157,7 +157,7 @@ Create a `timedelta` with the expiration time of the token.
 
 Create a real JWT access token and return it.
 
-```Python hl_lines="115 116 117 118 119 120 121 122 123 124 125 126 127 128"
+```Python hl_lines="116 117 118 119 120 121 122 123 124 125 126 127 128 129"
 {!../../../docs_src/security/tutorial004.py!}
 ```
 
diff --git a/docs/en/docs/tutorial/security/simple-oauth2.md b/docs/en/docs/tutorial/security/simple-oauth2.md
index c95c6aa6b6..2f58a6d109 100644
--- a/docs/en/docs/tutorial/security/simple-oauth2.md
+++ b/docs/en/docs/tutorial/security/simple-oauth2.md
@@ -49,7 +49,7 @@ Now let's use the utilities provided by **FastAPI** to handle this.
 
 First, import `OAuth2PasswordRequestForm`, and use it as a dependency with `Depends` for the path `/token`:
 
-```Python hl_lines="2  74"
+```Python hl_lines="4  76"
 {!../../../docs_src/security/tutorial003.py!}
 ```
 
@@ -90,7 +90,7 @@ If there is no such user, we return an error saying "incorrect username or passw
 
 For the error, we use the exception `HTTPException`:
 
-```Python hl_lines="1  75 76 77"
+```Python hl_lines="3  77 78 79"
 {!../../../docs_src/security/tutorial003.py!}
 ```
 
@@ -118,7 +118,7 @@ If your database is stolen, the thief won't have your users' plaintext passwords
 
 So, the thief won't be able to try to use those same passwords in another system (as many users use the same password everywhere, this would be dangerous).
 
-```Python hl_lines="78 79 80 81"
+```Python hl_lines="80 81 82 83"
 {!../../../docs_src/security/tutorial003.py!}
 ```
 
@@ -156,7 +156,7 @@ For this simple example, we are going to just be completely insecure and return
 
     But for now, let's focus on the specific details we need.
 
-```Python hl_lines="83"
+```Python hl_lines="85"
 {!../../../docs_src/security/tutorial003.py!}
 ```
 
@@ -181,7 +181,7 @@ Both of these dependencies will just return an HTTP error if the user doesn't ex
 
 So, in our endpoint, we will only get a user if the user exists, was correctly authenticated, and is active:
 
-```Python hl_lines="56 57 58 59 60 61 62 63 64 65  67 68 69 70  88"
+```Python hl_lines="58 59 60 61 62 63 64 65 66 67  69 70 71 72  90"
 {!../../../docs_src/security/tutorial003.py!}
 ```
 
diff --git a/docs/es/docs/index.md b/docs/es/docs/index.md
index e795f9578a..c2690b140a 100644
--- a/docs/es/docs/index.md
+++ b/docs/es/docs/index.md
@@ -131,6 +131,7 @@ $ pip install uvicorn
 
 ```Python
 from fastapi import FastAPI
+from typing import Optional
 
 app = FastAPI()
 
@@ -141,7 +142,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -152,6 +153,7 @@ Si tu código usa `async` / `await`, usa `async def`:
 
 ```Python hl_lines="7 12"
 from fastapi import FastAPI
+from typing import Optional
 
 app = FastAPI()
 
@@ -162,7 +164,7 @@ async def read_root():
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: int, q: str = None):
+async def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -243,6 +245,7 @@ Declara el body usando las declaraciones de tipo estándares de Python gracias a
 ```Python hl_lines="2  7 8 9 10  23 24 25"
 from fastapi import FastAPI
 from pydantic import BaseModel
+from typing import Optional
 
 app = FastAPI()
 
@@ -250,7 +253,7 @@ app = FastAPI()
 class Item(BaseModel):
     name: str
     price: float
-    is_offer: bool = None
+    is_offer: Optional[bool] = None
 
 
 @app.get("/")
@@ -259,7 +262,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 
 
diff --git a/docs/it/docs/index.md b/docs/it/docs/index.md
index 20dd403ab7..88d0c0e3d2 100644
--- a/docs/it/docs/index.md
+++ b/docs/it/docs/index.md
@@ -136,6 +136,7 @@ $ pip install uvicorn
 
 ```Python
 from fastapi import FastAPI
+from typing import Optional
 
 app = FastAPI()
 
@@ -146,7 +147,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: str = Optional[None]):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -157,6 +158,7 @@ If your code uses `async` / `await`, use `async def`:
 
 ```Python hl_lines="7 12"
 from fastapi import FastAPI
+from typing import Optional
 
 app = FastAPI()
 
@@ -167,7 +169,7 @@ async def read_root():
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: int, q: str = None):
+async def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -248,6 +250,7 @@ Declare the body using standard Python types, thanks to Pydantic.
 ```Python hl_lines="2  7 8 9 10  23 24 25"
 from fastapi import FastAPI
 from pydantic import BaseModel
+from typing import Optional
 
 app = FastAPI()
 
@@ -255,7 +258,7 @@ app = FastAPI()
 class Item(BaseModel):
     name: str
     price: float
-    is_offer: bool = None
+    is_offer: bool = Optional[None]
 
 
 @app.get("/")
@@ -264,7 +267,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 
 
diff --git a/docs/pt/docs/index.md b/docs/pt/docs/index.md
index 10b2d6855f..20600eeadb 100644
--- a/docs/pt/docs/index.md
+++ b/docs/pt/docs/index.md
@@ -124,6 +124,8 @@ $ pip install uvicorn
 * Crie um arquivo `main.py` com:
 
 ```Python
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -135,7 +137,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -144,7 +146,9 @@ def read_item(item_id: int, q: str = None):
 
 Se seu código utiliza `async` / `await`, use `async def`:
 
-```Python hl_lines="7 12"
+```Python hl_lines="9 14"
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -156,7 +160,7 @@ async def read_root():
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: int, q: str = None):
+async def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -234,7 +238,7 @@ Agora modifique o arquivo `main.py` para receber um corpo para uma requisição
 
 Declare o corpo utilizando tipos padrão Python, graças ao Pydantic.
 
-```Python hl_lines="2  7 8 9 10  23 24 25"
+```Python hl_lines="4  9 10 11 12  25 26 27"
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -244,7 +248,7 @@ app = FastAPI()
 class Item(BaseModel):
     name: str
     price: float
-    is_offer: bool = None
+    is_offer: Optional[bool] = None
 
 
 @app.get("/")
@@ -253,7 +257,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 
 
diff --git a/docs/ru/docs/index.md b/docs/ru/docs/index.md
index 20dd403ab7..5d5e806e58 100644
--- a/docs/ru/docs/index.md
+++ b/docs/ru/docs/index.md
@@ -135,6 +135,8 @@ $ pip install uvicorn
 * Create a file `main.py` with:
 
 ```Python
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -146,7 +148,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -155,7 +157,9 @@ def read_item(item_id: int, q: str = None):
 
 If your code uses `async` / `await`, use `async def`:
 
-```Python hl_lines="7 12"
+```Python hl_lines="9 14"
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -167,7 +171,7 @@ async def read_root():
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: int, q: str = None):
+async def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -245,7 +249,9 @@ Now modify the file `main.py` to receive a body from a `PUT` request.
 
 Declare the body using standard Python types, thanks to Pydantic.
 
-```Python hl_lines="2  7 8 9 10  23 24 25"
+```Python hl_lines="4  9 10 11 12  25 26 27"
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -255,7 +261,7 @@ app = FastAPI()
 class Item(BaseModel):
     name: str
     price: float
-    is_offer: bool = None
+    is_offer: Optional[bool] = None
 
 
 @app.get("/")
@@ -264,7 +270,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 
 
diff --git a/docs/zh/docs/deployment.md b/docs/zh/docs/deployment.md
index 6eb25824a7..8cca1091ed 100644
--- a/docs/zh/docs/deployment.md
+++ b/docs/zh/docs/deployment.md
@@ -162,6 +162,8 @@ CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "80"]
 * 创建一个 `main.py` 文件，内容如下：
 
 ```Python
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -173,7 +175,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
diff --git a/docs/zh/docs/index.md b/docs/zh/docs/index.md
index e8427c90bb..f3fac28d9d 100644
--- a/docs/zh/docs/index.md
+++ b/docs/zh/docs/index.md
@@ -131,6 +131,8 @@ $ pip install uvicorn
 * 创建一个 `main.py` 文件并写入以下内容:
 
 ```Python
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -142,7 +144,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -151,7 +153,9 @@ def read_item(item_id: int, q: str = None):
 
 如果你的代码里会出现 `async` / `await`，请使用 `async def`：
 
-```Python hl_lines="7 12"
+```Python hl_lines="9 14"
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -163,7 +167,7 @@ async def read_root():
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: int, q: str = None):
+async def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 ```
 
@@ -241,7 +245,9 @@ INFO:     Application startup complete.
 
 我们借助 Pydantic 来使用标准的 Python 类型声明请求体。
 
-```Python hl_lines="2  7 8 9 10  23 24 25"
+```Python hl_lines="4  9 10 11 12  25 26 27"
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -251,7 +257,7 @@ app = FastAPI()
 class Item(BaseModel):
     name: str
     price: float
-    is_offer: bool = None
+    is_offer: Optional[bool] = None
 
 
 @app.get("/")
@@ -260,7 +266,7 @@ def read_root():
 
 
 @app.get("/items/{item_id}")
-def read_item(item_id: int, q: str = None):
+def read_item(item_id: int, q: Optional[str] = None):
     return {"item_id": item_id, "q": q}
 
 
diff --git a/docs_src/additional_responses/tutorial002.py b/docs_src/additional_responses/tutorial002.py
index 28bdb9b2a4..a46e959596 100644
--- a/docs_src/additional_responses/tutorial002.py
+++ b/docs_src/additional_responses/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from fastapi.responses import FileResponse
 from pydantic import BaseModel
@@ -21,7 +23,7 @@ app = FastAPI()
         }
     },
 )
-async def read_item(item_id: str, img: bool = None):
+async def read_item(item_id: str, img: Optional[bool] = None):
     if img:
         return FileResponse("image.png", media_type="image/png")
     else:
diff --git a/docs_src/additional_responses/tutorial004.py b/docs_src/additional_responses/tutorial004.py
index f1b15fee13..361aecb8e7 100644
--- a/docs_src/additional_responses/tutorial004.py
+++ b/docs_src/additional_responses/tutorial004.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from fastapi.responses import FileResponse
 from pydantic import BaseModel
@@ -23,7 +25,7 @@ app = FastAPI()
     response_model=Item,
     responses={**responses, 200: {"content": {"image/png": {}}}},
 )
-async def read_item(item_id: str, img: bool = None):
+async def read_item(item_id: str, img: Optional[bool] = None):
     if img:
         return FileResponse("image.png", media_type="image/png")
     else:
diff --git a/docs_src/additional_status_codes/tutorial001.py b/docs_src/additional_status_codes/tutorial001.py
index c1b88828dd..ae101e0a09 100644
--- a/docs_src/additional_status_codes/tutorial001.py
+++ b/docs_src/additional_status_codes/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Body, FastAPI, status
 from fastapi.responses import JSONResponse
 
@@ -7,7 +9,9 @@ items = {"foo": {"name": "Fighters", "size": 6}, "bar": {"name": "Tenders", "siz
 
 
 @app.put("/items/{item_id}")
-async def upsert_item(item_id: str, name: str = Body(None), size: int = Body(None)):
+async def upsert_item(
+    item_id: str, name: Optional[str] = Body(None), size: Optional[int] = Body(None)
+):
     if item_id in items:
         item = items[item_id]
         item["name"] = name
diff --git a/docs_src/app_testing/main_b.py b/docs_src/app_testing/main_b.py
index cb9ced094e..df43db8060 100644
--- a/docs_src/app_testing/main_b.py
+++ b/docs_src/app_testing/main_b.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI, Header, HTTPException
 from pydantic import BaseModel
 
@@ -14,7 +16,7 @@ app = FastAPI()
 class Item(BaseModel):
     id: str
     title: str
-    description: str = None
+    description: Optional[str] = None
 
 
 @app.get("/items/{item_id}", response_model=Item)
diff --git a/docs_src/background_tasks/tutorial002.py b/docs_src/background_tasks/tutorial002.py
index 9fe7370123..e7517e8cde 100644
--- a/docs_src/background_tasks/tutorial002.py
+++ b/docs_src/background_tasks/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import BackgroundTasks, Depends, FastAPI
 
 app = FastAPI()
@@ -8,7 +10,7 @@ def write_log(message: str):
         log.write(message)
 
 
-def get_query(background_tasks: BackgroundTasks, q: str = None):
+def get_query(background_tasks: BackgroundTasks, q: Optional[str] = None):
     if q:
         message = f"found query: {q}\n"
         background_tasks.add_task(write_log, message)
diff --git a/docs_src/body/tutorial001.py b/docs_src/body/tutorial001.py
index e99a46ccc8..52144bd2b0 100644
--- a/docs_src/body/tutorial001.py
+++ b/docs_src/body/tutorial001.py
@@ -1,12 +1,14 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 app = FastAPI()
diff --git a/docs_src/body/tutorial002.py b/docs_src/body/tutorial002.py
index cce5eca49f..644fabae99 100644
--- a/docs_src/body/tutorial002.py
+++ b/docs_src/body/tutorial002.py
@@ -1,12 +1,14 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 app = FastAPI()
diff --git a/docs_src/body/tutorial003.py b/docs_src/body/tutorial003.py
index 1d3e902400..c99ea694b6 100644
--- a/docs_src/body/tutorial003.py
+++ b/docs_src/body/tutorial003.py
@@ -1,12 +1,14 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 app = FastAPI()
diff --git a/docs_src/body/tutorial004.py b/docs_src/body/tutorial004.py
index c389af2419..7a222a390e 100644
--- a/docs_src/body/tutorial004.py
+++ b/docs_src/body/tutorial004.py
@@ -1,19 +1,21 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 app = FastAPI()
 
 
 @app.put("/items/{item_id}")
-async def create_item(item_id: int, item: Item, q: str = None):
+async def create_item(item_id: int, item: Item, q: Optional[str] = None):
     result = {"item_id": item_id, **item.dict()}
     if q:
         result.update({"q": q})
diff --git a/docs_src/body_fields/tutorial001.py b/docs_src/body_fields/tutorial001.py
index dcd5b9764a..dabc48a0f5 100644
--- a/docs_src/body_fields/tutorial001.py
+++ b/docs_src/body_fields/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Body, FastAPI
 from pydantic import BaseModel, Field
 
@@ -6,9 +8,11 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = Field(None, title="The description of the item", max_length=300)
+    description: Optional[str] = Field(
+        None, title="The description of the item", max_length=300
+    )
     price: float = Field(..., gt=0, description="The price must be greater than zero")
-    tax: float = None
+    tax: Optional[float] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/body_multiple_params/tutorial001.py b/docs_src/body_multiple_params/tutorial001.py
index fbd368207c..7ce0ae6f28 100644
--- a/docs_src/body_multiple_params/tutorial001.py
+++ b/docs_src/body_multiple_params/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI, Path
 from pydantic import BaseModel
 
@@ -6,17 +8,17 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 @app.put("/items/{item_id}")
 async def update_item(
     *,
     item_id: int = Path(..., title="The ID of the item to get", ge=0, le=1000),
-    q: str = None,
-    item: Item = None,
+    q: Optional[str] = None,
+    item: Optional[Item] = None,
 ):
     results = {"item_id": item_id}
     if q:
diff --git a/docs_src/body_multiple_params/tutorial002.py b/docs_src/body_multiple_params/tutorial002.py
index 54f6d9138b..6b87484203 100644
--- a/docs_src/body_multiple_params/tutorial002.py
+++ b/docs_src/body_multiple_params/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -6,14 +8,14 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 class User(BaseModel):
     username: str
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/body_multiple_params/tutorial003.py b/docs_src/body_multiple_params/tutorial003.py
index 691fe848b6..7e9e243748 100644
--- a/docs_src/body_multiple_params/tutorial003.py
+++ b/docs_src/body_multiple_params/tutorial003.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Body, FastAPI
 from pydantic import BaseModel
 
@@ -6,14 +8,14 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 class User(BaseModel):
     username: str
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/body_multiple_params/tutorial004.py b/docs_src/body_multiple_params/tutorial004.py
index 359b33cccb..8dc0d374de 100644
--- a/docs_src/body_multiple_params/tutorial004.py
+++ b/docs_src/body_multiple_params/tutorial004.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Body, FastAPI
 from pydantic import BaseModel
 
@@ -6,14 +8,14 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 class User(BaseModel):
     username: str
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 @app.put("/items/{item_id}")
@@ -23,7 +25,7 @@ async def update_item(
     item: Item,
     user: User,
     importance: int = Body(..., gt=0),
-    q: str = None
+    q: Optional[str] = None
 ):
     results = {"item_id": item_id, "item": item, "user": user, "importance": importance}
     if q:
diff --git a/docs_src/body_multiple_params/tutorial005.py b/docs_src/body_multiple_params/tutorial005.py
index 606d3bbbb0..4657b4144e 100644
--- a/docs_src/body_multiple_params/tutorial005.py
+++ b/docs_src/body_multiple_params/tutorial005.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Body, FastAPI
 from pydantic import BaseModel
 
@@ -6,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/body_nested_models/tutorial001.py b/docs_src/body_nested_models/tutorial001.py
index 56db2a0938..fe14fdf93e 100644
--- a/docs_src/body_nested_models/tutorial001.py
+++ b/docs_src/body_nested_models/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -6,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: list = []
 
 
diff --git a/docs_src/body_nested_models/tutorial002.py b/docs_src/body_nested_models/tutorial002.py
index db33e483f4..1770516a45 100644
--- a/docs_src/body_nested_models/tutorial002.py
+++ b/docs_src/body_nested_models/tutorial002.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: List[str] = []
 
 
diff --git a/docs_src/body_nested_models/tutorial003.py b/docs_src/body_nested_models/tutorial003.py
index f65195b620..33dbbe3a9e 100644
--- a/docs_src/body_nested_models/tutorial003.py
+++ b/docs_src/body_nested_models/tutorial003.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = set()
 
 
diff --git a/docs_src/body_nested_models/tutorial004.py b/docs_src/body_nested_models/tutorial004.py
index 6c2ca25eb7..6037b32b77 100644
--- a/docs_src/body_nested_models/tutorial004.py
+++ b/docs_src/body_nested_models/tutorial004.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
-    image: Image = None
+    image: Optional[Image] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/body_nested_models/tutorial005.py b/docs_src/body_nested_models/tutorial005.py
index d6d9d6479e..0c076d4f9f 100644
--- a/docs_src/body_nested_models/tutorial005.py
+++ b/docs_src/body_nested_models/tutorial005.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
-    image: Image = None
+    image: Optional[Image] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/body_nested_models/tutorial006.py b/docs_src/body_nested_models/tutorial006.py
index d64668518e..1d2b4ce470 100644
--- a/docs_src/body_nested_models/tutorial006.py
+++ b/docs_src/body_nested_models/tutorial006.py
@@ -1,4 +1,4 @@
-from typing import List, Set
+from typing import List, Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
-    images: List[Image] = None
+    images: Optional[List[Image]] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/body_nested_models/tutorial007.py b/docs_src/body_nested_models/tutorial007.py
index f4b699dbfb..9f321643ce 100644
--- a/docs_src/body_nested_models/tutorial007.py
+++ b/docs_src/body_nested_models/tutorial007.py
@@ -1,4 +1,4 @@
-from typing import List, Set
+from typing import List, Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,16 +13,16 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
-    images: List[Image] = None
+    images: Optional[List[Image]] = None
 
 
 class Offer(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
     items: List[Item]
 
diff --git a/docs_src/body_updates/tutorial001.py b/docs_src/body_updates/tutorial001.py
index bf92493273..9b8f3ccf1b 100644
--- a/docs_src/body_updates/tutorial001.py
+++ b/docs_src/body_updates/tutorial001.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -8,9 +8,9 @@ app = FastAPI()
 
 
 class Item(BaseModel):
-    name: str = None
-    description: str = None
-    price: float = None
+    name: Optional[str] = None
+    description: Optional[str] = None
+    price: Optional[float] = None
     tax: float = 10.5
     tags: List[str] = []
 
diff --git a/docs_src/body_updates/tutorial002.py b/docs_src/body_updates/tutorial002.py
index 56cb8c4dce..46d27e67e7 100644
--- a/docs_src/body_updates/tutorial002.py
+++ b/docs_src/body_updates/tutorial002.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -8,9 +8,9 @@ app = FastAPI()
 
 
 class Item(BaseModel):
-    name: str = None
-    description: str = None
-    price: float = None
+    name: Optional[str] = None
+    description: Optional[str] = None
+    price: Optional[float] = None
     tax: float = 10.5
     tags: List[str] = []
 
diff --git a/docs_src/cookie_params/tutorial001.py b/docs_src/cookie_params/tutorial001.py
index bee934b067..67d03b1336 100644
--- a/docs_src/cookie_params/tutorial001.py
+++ b/docs_src/cookie_params/tutorial001.py
@@ -1,8 +1,10 @@
+from typing import Optional
+
 from fastapi import Cookie, FastAPI
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(ads_id: str = Cookie(None)):
+async def read_items(ads_id: Optional[str] = Cookie(None)):
     return {"ads_id": ads_id}
diff --git a/docs_src/dependencies/tutorial001.py b/docs_src/dependencies/tutorial001.py
index 131a471a1d..a9da971dc0 100644
--- a/docs_src/dependencies/tutorial001.py
+++ b/docs_src/dependencies/tutorial001.py
@@ -1,9 +1,11 @@
+from typing import Optional
+
 from fastapi import Depends, FastAPI
 
 app = FastAPI()
 
 
-async def common_parameters(q: str = None, skip: int = 0, limit: int = 100):
+async def common_parameters(q: Optional[str] = None, skip: int = 0, limit: int = 100):
     return {"q": q, "skip": skip, "limit": limit}
 
 
diff --git a/docs_src/dependencies/tutorial002.py b/docs_src/dependencies/tutorial002.py
index 9733c60c8b..458f6b5bb2 100644
--- a/docs_src/dependencies/tutorial002.py
+++ b/docs_src/dependencies/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Depends, FastAPI
 
 app = FastAPI()
@@ -7,7 +9,7 @@ fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"
 
 
 class CommonQueryParams:
-    def __init__(self, q: str = None, skip: int = 0, limit: int = 100):
+    def __init__(self, q: Optional[str] = None, skip: int = 0, limit: int = 100):
         self.q = q
         self.skip = skip
         self.limit = limit
diff --git a/docs_src/dependencies/tutorial003.py b/docs_src/dependencies/tutorial003.py
index 3f73619682..3f3e940f81 100644
--- a/docs_src/dependencies/tutorial003.py
+++ b/docs_src/dependencies/tutorial003.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Depends, FastAPI
 
 app = FastAPI()
@@ -7,7 +9,7 @@ fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"
 
 
 class CommonQueryParams:
-    def __init__(self, q: str = None, skip: int = 0, limit: int = 100):
+    def __init__(self, q: Optional[str] = None, skip: int = 0, limit: int = 100):
         self.q = q
         self.skip = skip
         self.limit = limit
diff --git a/docs_src/dependencies/tutorial004.py b/docs_src/dependencies/tutorial004.py
index 6c7ca48210..daa7b46703 100644
--- a/docs_src/dependencies/tutorial004.py
+++ b/docs_src/dependencies/tutorial004.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Depends, FastAPI
 
 app = FastAPI()
@@ -7,7 +9,7 @@ fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"
 
 
 class CommonQueryParams:
-    def __init__(self, q: str = None, skip: int = 0, limit: int = 100):
+    def __init__(self, q: Optional[str] = None, skip: int = 0, limit: int = 100):
         self.q = q
         self.skip = skip
         self.limit = limit
diff --git a/docs_src/dependencies/tutorial005.py b/docs_src/dependencies/tutorial005.py
index 36b312352d..c8923d143d 100644
--- a/docs_src/dependencies/tutorial005.py
+++ b/docs_src/dependencies/tutorial005.py
@@ -1,14 +1,16 @@
+from typing import Optional
+
 from fastapi import Cookie, Depends, FastAPI
 
 app = FastAPI()
 
 
-def query_extractor(q: str = None):
+def query_extractor(q: Optional[str] = None):
     return q
 
 
 def query_or_cookie_extractor(
-    q: str = Depends(query_extractor), last_query: str = Cookie(None)
+    q: str = Depends(query_extractor), last_query: Optional[str] = Cookie(None)
 ):
     if not q:
         return last_query
diff --git a/docs_src/dependency_testing/tutorial001.py b/docs_src/dependency_testing/tutorial001.py
index 67c3874a36..237d3b2310 100644
--- a/docs_src/dependency_testing/tutorial001.py
+++ b/docs_src/dependency_testing/tutorial001.py
@@ -1,10 +1,12 @@
+from typing import Optional
+
 from fastapi import Depends, FastAPI
 from fastapi.testclient import TestClient
 
 app = FastAPI()
 
 
-async def common_parameters(q: str = None, skip: int = 0, limit: int = 100):
+async def common_parameters(q: Optional[str] = None, skip: int = 0, limit: int = 100):
     return {"q": q, "skip": skip, "limit": limit}
 
 
@@ -21,7 +23,7 @@ async def read_users(commons: dict = Depends(common_parameters)):
 client = TestClient(app)
 
 
-async def override_dependency(q: str = None):
+async def override_dependency(q: Optional[str] = None):
     return {"q": q, "skip": 5, "limit": 10}
 
 
diff --git a/docs_src/encoder/tutorial001.py b/docs_src/encoder/tutorial001.py
index 11984dd96a..a918fdd64a 100644
--- a/docs_src/encoder/tutorial001.py
+++ b/docs_src/encoder/tutorial001.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+from typing import Optional
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -10,7 +11,7 @@ fake_db = {}
 class Item(BaseModel):
     title: str
     timestamp: datetime
-    description: str = None
+    description: Optional[str] = None
 
 
 app = FastAPI()
diff --git a/docs_src/extra_data_types/tutorial001.py b/docs_src/extra_data_types/tutorial001.py
index 2b6d2f7b99..e8d7e1ea32 100644
--- a/docs_src/extra_data_types/tutorial001.py
+++ b/docs_src/extra_data_types/tutorial001.py
@@ -1,4 +1,5 @@
 from datetime import datetime, time, timedelta
+from typing import Optional
 from uuid import UUID
 
 from fastapi import Body, FastAPI
@@ -9,10 +10,10 @@ app = FastAPI()
 @app.put("/items/{item_id}")
 async def read_items(
     item_id: UUID,
-    start_datetime: datetime = Body(None),
-    end_datetime: datetime = Body(None),
-    repeat_at: time = Body(None),
-    process_after: timedelta = Body(None),
+    start_datetime: Optional[datetime] = Body(None),
+    end_datetime: Optional[datetime] = Body(None),
+    repeat_at: Optional[time] = Body(None),
+    process_after: Optional[timedelta] = Body(None),
 ):
     start_process = start_datetime + process_after
     duration = end_datetime - start_process
diff --git a/docs_src/extra_models/tutorial001.py b/docs_src/extra_models/tutorial001.py
index 7ff4bba7ea..e95844f608 100644
--- a/docs_src/extra_models/tutorial001.py
+++ b/docs_src/extra_models/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
 
@@ -8,20 +10,20 @@ class UserIn(BaseModel):
     username: str
     password: str
     email: EmailStr
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 class UserOut(BaseModel):
     username: str
     email: EmailStr
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 class UserInDB(BaseModel):
     username: str
     hashed_password: str
     email: EmailStr
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 def fake_password_hasher(raw_password: str):
diff --git a/docs_src/extra_models/tutorial002.py b/docs_src/extra_models/tutorial002.py
index 0306991140..5bc6e707fa 100644
--- a/docs_src/extra_models/tutorial002.py
+++ b/docs_src/extra_models/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
 
@@ -7,7 +9,7 @@ app = FastAPI()
 class UserBase(BaseModel):
     username: str
     email: EmailStr
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 class UserIn(UserBase):
diff --git a/docs_src/header_params/tutorial001.py b/docs_src/header_params/tutorial001.py
index e871de68d7..7d69b027ee 100644
--- a/docs_src/header_params/tutorial001.py
+++ b/docs_src/header_params/tutorial001.py
@@ -1,8 +1,10 @@
+from typing import Optional
+
 from fastapi import FastAPI, Header
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(user_agent: str = Header(None)):
+async def read_items(user_agent: Optional[str] = Header(None)):
     return {"User-Agent": user_agent}
diff --git a/docs_src/header_params/tutorial002.py b/docs_src/header_params/tutorial002.py
index ba6cef1ded..2de3dddd70 100644
--- a/docs_src/header_params/tutorial002.py
+++ b/docs_src/header_params/tutorial002.py
@@ -1,8 +1,12 @@
+from typing import Optional
+
 from fastapi import FastAPI, Header
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(strange_header: str = Header(None, convert_underscores=False)):
+async def read_items(
+    strange_header: Optional[str] = Header(None, convert_underscores=False)
+):
     return {"strange_header": strange_header}
diff --git a/docs_src/header_params/tutorial003.py b/docs_src/header_params/tutorial003.py
index 85d0fb3a28..6d0eefdd21 100644
--- a/docs_src/header_params/tutorial003.py
+++ b/docs_src/header_params/tutorial003.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI, Header
 
@@ -6,5 +6,5 @@ app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(x_token: List[str] = Header(None)):
+async def read_items(x_token: Optional[List[str]] = Header(None)):
     return {"X-Token values": x_token}
diff --git a/docs_src/openapi_callbacks/tutorial001.py b/docs_src/openapi_callbacks/tutorial001.py
index c9ca4eb96a..dea7e89b43 100644
--- a/docs_src/openapi_callbacks/tutorial001.py
+++ b/docs_src/openapi_callbacks/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import APIRouter, FastAPI
 from fastapi.responses import JSONResponse
 from pydantic import BaseModel, HttpUrl
@@ -7,7 +9,7 @@ app = FastAPI()
 
 class Invoice(BaseModel):
     id: str
-    title: str = None
+    title: Optional[str] = None
     customer: str
     total: float
 
@@ -32,7 +34,7 @@ def invoice_notification(body: InvoiceEvent):
 
 
 @app.post("/invoices/", callbacks=invoices_callback_router.routes)
-def create_invoice(invoice: Invoice, callback_url: HttpUrl = None):
+def create_invoice(invoice: Invoice, callback_url: Optional[HttpUrl] = None):
     """
     Create an invoice.
 
diff --git a/docs_src/path_operation_advanced_configuration/tutorial004.py b/docs_src/path_operation_advanced_configuration/tutorial004.py
index 24be0cb940..fa867e794b 100644
--- a/docs_src/path_operation_advanced_configuration/tutorial004.py
+++ b/docs_src/path_operation_advanced_configuration/tutorial004.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
 
 
diff --git a/docs_src/path_operation_configuration/tutorial001.py b/docs_src/path_operation_configuration/tutorial001.py
index 77437cd08a..66ea442ea9 100644
--- a/docs_src/path_operation_configuration/tutorial001.py
+++ b/docs_src/path_operation_configuration/tutorial001.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI, status
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
 
 
diff --git a/docs_src/path_operation_configuration/tutorial002.py b/docs_src/path_operation_configuration/tutorial002.py
index ed29ea014f..01df041b83 100644
--- a/docs_src/path_operation_configuration/tutorial002.py
+++ b/docs_src/path_operation_configuration/tutorial002.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
 
 
diff --git a/docs_src/path_operation_configuration/tutorial003.py b/docs_src/path_operation_configuration/tutorial003.py
index 4c4b048c7c..29bcb4a223 100644
--- a/docs_src/path_operation_configuration/tutorial003.py
+++ b/docs_src/path_operation_configuration/tutorial003.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
 
 
diff --git a/docs_src/path_operation_configuration/tutorial004.py b/docs_src/path_operation_configuration/tutorial004.py
index f9822aae42..ac95cc4bb9 100644
--- a/docs_src/path_operation_configuration/tutorial004.py
+++ b/docs_src/path_operation_configuration/tutorial004.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
 
 
diff --git a/docs_src/path_operation_configuration/tutorial005.py b/docs_src/path_operation_configuration/tutorial005.py
index 7ae2acafc3..c1b8098872 100644
--- a/docs_src/path_operation_configuration/tutorial005.py
+++ b/docs_src/path_operation_configuration/tutorial005.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: Set[str] = []
 
 
diff --git a/docs_src/path_params_numeric_validations/tutorial001.py b/docs_src/path_params_numeric_validations/tutorial001.py
index fc1911872c..11777bba77 100644
--- a/docs_src/path_params_numeric_validations/tutorial001.py
+++ b/docs_src/path_params_numeric_validations/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI, Path, Query
 
 app = FastAPI()
@@ -6,7 +8,7 @@ app = FastAPI()
 @app.get("/items/{item_id}")
 async def read_items(
     item_id: int = Path(..., title="The ID of the item to get"),
-    q: str = Query(None, alias="item-query"),
+    q: Optional[str] = Query(None, alias="item-query"),
 ):
     results = {"item_id": item_id}
     if q:
diff --git a/docs_src/query_params/tutorial002.py b/docs_src/query_params/tutorial002.py
index 6e93488176..32918465e5 100644
--- a/docs_src/query_params/tutorial002.py
+++ b/docs_src/query_params/tutorial002.py
@@ -1,10 +1,12 @@
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: str, q: str = None):
+async def read_item(item_id: str, q: Optional[str] = None):
     if q:
         return {"item_id": item_id, "q": q}
     return {"item_id": item_id}
diff --git a/docs_src/query_params/tutorial003.py b/docs_src/query_params/tutorial003.py
index bba18c4106..c81a967856 100644
--- a/docs_src/query_params/tutorial003.py
+++ b/docs_src/query_params/tutorial003.py
@@ -1,10 +1,12 @@
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: str, q: str = None, short: bool = False):
+async def read_item(item_id: str, q: Optional[str] = None, short: bool = False):
     item = {"item_id": item_id}
     if q:
         item.update({"q": q})
diff --git a/docs_src/query_params/tutorial004.py b/docs_src/query_params/tutorial004.py
index 4407baf9aa..37f97fa2ac 100644
--- a/docs_src/query_params/tutorial004.py
+++ b/docs_src/query_params/tutorial004.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
@@ -5,7 +7,7 @@ app = FastAPI()
 
 @app.get("/users/{user_id}/items/{item_id}")
 async def read_user_item(
-    user_id: int, item_id: str, q: str = None, short: bool = False
+    user_id: int, item_id: str, q: Optional[str] = None, short: bool = False
 ):
     item = {"item_id": item_id, "owner_id": user_id}
     if q:
diff --git a/docs_src/query_params/tutorial006.py b/docs_src/query_params/tutorial006.py
index d764c2a863..ffe3283403 100644
--- a/docs_src/query_params/tutorial006.py
+++ b/docs_src/query_params/tutorial006.py
@@ -1,9 +1,13 @@
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
 
 
 @app.get("/items/{item_id}")
-async def read_user_item(item_id: str, needy: str, skip: int = 0, limit: int = None):
+async def read_user_item(
+    item_id: str, needy: str, skip: int = 0, limit: Optional[int] = None
+):
     item = {"item_id": item_id, "needy": needy, "skip": skip, "limit": limit}
     return item
diff --git a/docs_src/query_params/tutorial007.py b/docs_src/query_params/tutorial007.py
deleted file mode 100644
index 8ef5b3004b..0000000000
--- a/docs_src/query_params/tutorial007.py
+++ /dev/null
@@ -1,11 +0,0 @@
-from typing import Optional
-
-from fastapi import FastAPI
-
-app = FastAPI()
-
-
-@app.get("/items/{item_id}")
-async def read_user_item(item_id: str, limit: Optional[int] = None):
-    item = {"item_id": item_id, "limit": limit}
-    return item
diff --git a/docs_src/query_params_str_validations/tutorial001.py b/docs_src/query_params_str_validations/tutorial001.py
index b06c33c3ee..5d7bfb0ee5 100644
--- a/docs_src/query_params_str_validations/tutorial001.py
+++ b/docs_src/query_params_str_validations/tutorial001.py
@@ -1,10 +1,12 @@
+from typing import Optional
+
 from fastapi import FastAPI
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: str = None):
+async def read_items(q: Optional[str] = None):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})
diff --git a/docs_src/query_params_str_validations/tutorial002.py b/docs_src/query_params_str_validations/tutorial002.py
index 183180cd74..68ea582061 100644
--- a/docs_src/query_params_str_validations/tutorial002.py
+++ b/docs_src/query_params_str_validations/tutorial002.py
@@ -1,10 +1,12 @@
+from typing import Optional
+
 from fastapi import FastAPI, Query
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: str = Query(None, max_length=50)):
+async def read_items(q: Optional[str] = Query(None, max_length=50)):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})
diff --git a/docs_src/query_params_str_validations/tutorial003.py b/docs_src/query_params_str_validations/tutorial003.py
index 311ece816a..e52acc72f0 100644
--- a/docs_src/query_params_str_validations/tutorial003.py
+++ b/docs_src/query_params_str_validations/tutorial003.py
@@ -1,10 +1,12 @@
+from typing import Optional
+
 from fastapi import FastAPI, Query
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: str = Query(None, min_length=3, max_length=50)):
+async def read_items(q: Optional[str] = Query(None, min_length=3, max_length=50)):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})
diff --git a/docs_src/query_params_str_validations/tutorial004.py b/docs_src/query_params_str_validations/tutorial004.py
index 785db44c0d..d2c30331f6 100644
--- a/docs_src/query_params_str_validations/tutorial004.py
+++ b/docs_src/query_params_str_validations/tutorial004.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI, Query
 
 app = FastAPI()
@@ -5,7 +7,7 @@ app = FastAPI()
 
 @app.get("/items/")
 async def read_items(
-    q: str = Query(None, min_length=3, max_length=50, regex="^fixedquery$")
+    q: Optional[str] = Query(None, min_length=3, max_length=50, regex="^fixedquery$")
 ):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
diff --git a/docs_src/query_params_str_validations/tutorial007.py b/docs_src/query_params_str_validations/tutorial007.py
index 76b9ea811d..e360feda9f 100644
--- a/docs_src/query_params_str_validations/tutorial007.py
+++ b/docs_src/query_params_str_validations/tutorial007.py
@@ -1,10 +1,14 @@
+from typing import Optional
+
 from fastapi import FastAPI, Query
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: str = Query(None, title="Query string", min_length=3)):
+async def read_items(
+    q: Optional[str] = Query(None, title="Query string", min_length=3)
+):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})
diff --git a/docs_src/query_params_str_validations/tutorial008.py b/docs_src/query_params_str_validations/tutorial008.py
index 339f80e933..238add4710 100644
--- a/docs_src/query_params_str_validations/tutorial008.py
+++ b/docs_src/query_params_str_validations/tutorial008.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI, Query
 
 app = FastAPI()
@@ -5,7 +7,7 @@ app = FastAPI()
 
 @app.get("/items/")
 async def read_items(
-    q: str = Query(
+    q: Optional[str] = Query(
         None,
         title="Query string",
         description="Query string for the items to search in the database that have a good match",
diff --git a/docs_src/query_params_str_validations/tutorial009.py b/docs_src/query_params_str_validations/tutorial009.py
index 7f50100144..7e5c0b81a8 100644
--- a/docs_src/query_params_str_validations/tutorial009.py
+++ b/docs_src/query_params_str_validations/tutorial009.py
@@ -1,10 +1,12 @@
+from typing import Optional
+
 from fastapi import FastAPI, Query
 
 app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: str = Query(None, alias="item-query")):
+async def read_items(q: Optional[str] = Query(None, alias="item-query")):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})
diff --git a/docs_src/query_params_str_validations/tutorial010.py b/docs_src/query_params_str_validations/tutorial010.py
index 051656c768..7921506b65 100644
--- a/docs_src/query_params_str_validations/tutorial010.py
+++ b/docs_src/query_params_str_validations/tutorial010.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI, Query
 
 app = FastAPI()
@@ -5,7 +7,7 @@ app = FastAPI()
 
 @app.get("/items/")
 async def read_items(
-    q: str = Query(
+    q: Optional[str] = Query(
         None,
         alias="item-query",
         title="Query string",
diff --git a/docs_src/query_params_str_validations/tutorial011.py b/docs_src/query_params_str_validations/tutorial011.py
index f1c0e5b5b1..7fda267edd 100644
--- a/docs_src/query_params_str_validations/tutorial011.py
+++ b/docs_src/query_params_str_validations/tutorial011.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI, Query
 
@@ -6,6 +6,6 @@ app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: List[str] = Query(None)):
+async def read_items(q: Optional[List[str]] = Query(None)):
     query_items = {"q": q}
     return query_items
diff --git a/docs_src/query_params_str_validations/tutorial013.py b/docs_src/query_params_str_validations/tutorial013.py
index a433b3a16e..95dd6999dd 100644
--- a/docs_src/query_params_str_validations/tutorial013.py
+++ b/docs_src/query_params_str_validations/tutorial013.py
@@ -4,6 +4,6 @@ app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: list = Query(None)):
+async def read_items(q: list = Query([])):
     query_items = {"q": q}
     return query_items
diff --git a/docs_src/response_directly/tutorial001.py b/docs_src/response_directly/tutorial001.py
index 89c5968b14..6acdc0fc8d 100644
--- a/docs_src/response_directly/tutorial001.py
+++ b/docs_src/response_directly/tutorial001.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+from typing import Optional
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -9,7 +10,7 @@ from pydantic import BaseModel
 class Item(BaseModel):
     title: str
     timestamp: datetime
-    description: str = None
+    description: Optional[str] = None
 
 
 app = FastAPI()
diff --git a/docs_src/response_model/tutorial001.py b/docs_src/response_model/tutorial001.py
index 4fe9aeb504..57992ecfc5 100644
--- a/docs_src/response_model/tutorial001.py
+++ b/docs_src/response_model/tutorial001.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
     tags: List[str] = []
 
 
diff --git a/docs_src/response_model/tutorial002.py b/docs_src/response_model/tutorial002.py
index 67084b45e9..373317eb93 100644
--- a/docs_src/response_model/tutorial002.py
+++ b/docs_src/response_model/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
 
@@ -8,7 +10,7 @@ class UserIn(BaseModel):
     username: str
     password: str
     email: EmailStr
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 # Don't do this in production!
diff --git a/docs_src/response_model/tutorial003.py b/docs_src/response_model/tutorial003.py
index 8450723c24..e14026dd8c 100644
--- a/docs_src/response_model/tutorial003.py
+++ b/docs_src/response_model/tutorial003.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
 
@@ -8,13 +10,13 @@ class UserIn(BaseModel):
     username: str
     password: str
     email: EmailStr
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 class UserOut(BaseModel):
     username: str
     email: EmailStr
-    full_name: str = None
+    full_name: Optional[str] = None
 
 
 @app.post("/user/", response_model=UserOut)
diff --git a/docs_src/response_model/tutorial004.py b/docs_src/response_model/tutorial004.py
index 7a2373e0cf..1e18f989dc 100644
--- a/docs_src/response_model/tutorial004.py
+++ b/docs_src/response_model/tutorial004.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,7 +8,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
     tax: float = 10.5
     tags: List[str] = []
diff --git a/docs_src/response_model/tutorial005.py b/docs_src/response_model/tutorial005.py
index 65343f0723..03933d1f71 100644
--- a/docs_src/response_model/tutorial005.py
+++ b/docs_src/response_model/tutorial005.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -6,7 +8,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
     tax: float = 10.5
 
diff --git a/docs_src/response_model/tutorial006.py b/docs_src/response_model/tutorial006.py
index 127c6f7cf6..629ab8a3aa 100644
--- a/docs_src/response_model/tutorial006.py
+++ b/docs_src/response_model/tutorial006.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -6,7 +8,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
     tax: float = 10.5
 
diff --git a/docs_src/schema_extra_example/tutorial001.py b/docs_src/schema_extra_example/tutorial001.py
index 59a5837503..fab4d7a445 100644
--- a/docs_src/schema_extra_example/tutorial001.py
+++ b/docs_src/schema_extra_example/tutorial001.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -6,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
     class Config:
         schema_extra = {
diff --git a/docs_src/schema_extra_example/tutorial002.py b/docs_src/schema_extra_example/tutorial002.py
index 0a567bd79e..df3df88547 100644
--- a/docs_src/schema_extra_example/tutorial002.py
+++ b/docs_src/schema_extra_example/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from pydantic import BaseModel, Field
 
@@ -6,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str = Field(..., example="Foo")
-    description: str = Field(None, example="A very nice Item")
+    description: Optional[str] = Field(None, example="A very nice Item")
     price: float = Field(..., example=35.4)
-    tax: float = Field(None, example=3.2)
+    tax: Optional[float] = Field(None, example=3.2)
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/schema_extra_example/tutorial003.py b/docs_src/schema_extra_example/tutorial003.py
index 87fbefbb6f..58c79f5543 100644
--- a/docs_src/schema_extra_example/tutorial003.py
+++ b/docs_src/schema_extra_example/tutorial003.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Body, FastAPI
 from pydantic import BaseModel
 
@@ -6,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     price: float
-    tax: float = None
+    tax: Optional[float] = None
 
 
 @app.put("/items/{item_id}")
diff --git a/docs_src/security/tutorial003.py b/docs_src/security/tutorial003.py
index 5dabb393f1..0fd15ae3c7 100644
--- a/docs_src/security/tutorial003.py
+++ b/docs_src/security/tutorial003.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Depends, FastAPI, HTTPException, status
 from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
 from pydantic import BaseModel
@@ -31,9 +33,9 @@ oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/token")
 
 class User(BaseModel):
     username: str
-    email: str = None
-    full_name: str = None
-    disabled: bool = None
+    email: Optional[str] = None
+    full_name: Optional[str] = None
+    disabled: Optional[bool] = None
 
 
 class UserInDB(User):
diff --git a/docs_src/security/tutorial004.py b/docs_src/security/tutorial004.py
index 56f0eb0ea4..f3cb6a905b 100644
--- a/docs_src/security/tutorial004.py
+++ b/docs_src/security/tutorial004.py
@@ -1,4 +1,5 @@
 from datetime import datetime, timedelta
+from typing import Optional
 
 import jwt
 from fastapi import Depends, FastAPI, HTTPException, status
@@ -31,14 +32,14 @@ class Token(BaseModel):
 
 
 class TokenData(BaseModel):
-    username: str = None
+    username: Optional[str] = None
 
 
 class User(BaseModel):
     username: str
-    email: str = None
-    full_name: str = None
-    disabled: bool = None
+    email: Optional[str] = None
+    full_name: Optional[str] = None
+    disabled: Optional[bool] = None
 
 
 class UserInDB(User):
@@ -75,7 +76,7 @@ def authenticate_user(fake_db, username: str, password: str):
     return user
 
 
-def create_access_token(data: dict, expires_delta: timedelta = None):
+def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
     to_encode = data.copy()
     if expires_delta:
         expire = datetime.utcnow() + expires_delta
diff --git a/docs_src/security/tutorial005.py b/docs_src/security/tutorial005.py
index 489404d6f3..05c29deb19 100644
--- a/docs_src/security/tutorial005.py
+++ b/docs_src/security/tutorial005.py
@@ -1,5 +1,5 @@
 from datetime import datetime, timedelta
-from typing import List
+from typing import List, Optional
 
 import jwt
 from fastapi import Depends, FastAPI, HTTPException, Security, status
@@ -43,15 +43,15 @@ class Token(BaseModel):
 
 
 class TokenData(BaseModel):
-    username: str = None
+    username: Optional[str] = None
     scopes: List[str] = []
 
 
 class User(BaseModel):
     username: str
-    email: str = None
-    full_name: str = None
-    disabled: bool = None
+    email: Optional[str] = None
+    full_name: Optional[str] = None
+    disabled: Optional[bool] = None
 
 
 class UserInDB(User):
@@ -91,7 +91,7 @@ def authenticate_user(fake_db, username: str, password: str):
     return user
 
 
-def create_access_token(data: dict, expires_delta: timedelta = None):
+def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
     to_encode = data.copy()
     if expires_delta:
         expire = datetime.utcnow() + expires_delta
diff --git a/docs_src/sql_databases/sql_app/schemas.py b/docs_src/sql_databases/sql_app/schemas.py
index 5f964f0a6f..51655663a0 100644
--- a/docs_src/sql_databases/sql_app/schemas.py
+++ b/docs_src/sql_databases/sql_app/schemas.py
@@ -1,11 +1,11 @@
-from typing import List
+from typing import List, Optional
 
 from pydantic import BaseModel
 
 
 class ItemBase(BaseModel):
     title: str
-    description: str = None
+    description: Optional[str] = None
 
 
 class ItemCreate(ItemBase):
diff --git a/docs_src/sql_databases_peewee/sql_app/schemas.py b/docs_src/sql_databases_peewee/sql_app/schemas.py
index 0bb9215a83..b715604eec 100644
--- a/docs_src/sql_databases_peewee/sql_app/schemas.py
+++ b/docs_src/sql_databases_peewee/sql_app/schemas.py
@@ -1,4 +1,4 @@
-from typing import Any, List
+from typing import Any, List, Optional
 
 import peewee
 from pydantic import BaseModel
@@ -15,7 +15,7 @@ class PeeweeGetterDict(GetterDict):
 
 class ItemBase(BaseModel):
     title: str
-    description: str = None
+    description: Optional[str] = None
 
 
 class ItemCreate(ItemBase):
diff --git a/docs_src/websockets/tutorial002.py b/docs_src/websockets/tutorial002.py
index 5be199cd66..53cdb41ff1 100644
--- a/docs_src/websockets/tutorial002.py
+++ b/docs_src/websockets/tutorial002.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import Cookie, Depends, FastAPI, Query, WebSocket, status
 from fastapi.responses import HTMLResponse
 
@@ -54,7 +56,9 @@ async def get():
 
 
 async def get_cookie_or_token(
-    websocket: WebSocket, session: str = Cookie(None), token: str = Query(None)
+    websocket: WebSocket,
+    session: Optional[str] = Cookie(None),
+    token: Optional[str] = Query(None),
 ):
     if session is None and token is None:
         await websocket.close(code=status.WS_1008_POLICY_VIOLATION)
@@ -65,7 +69,7 @@ async def get_cookie_or_token(
 async def websocket_endpoint(
     websocket: WebSocket,
     item_id: str,
-    q: int = None,
+    q: Optional[int] = None,
     cookie_or_token: str = Depends(get_cookie_or_token),
 ):
     await websocket.accept()
diff --git a/tests/main.py b/tests/main.py
index f32856cb6c..35b7870560 100644
--- a/tests/main.py
+++ b/tests/main.py
@@ -1,4 +1,5 @@
 import http
+from typing import Optional
 
 from fastapi import FastAPI, Path, Query
 
@@ -48,7 +49,7 @@ def get_bool_id(item_id: bool):
 
 
 @app.get("/path/param/{item_id}")
-def get_path_param_id(item_id: str = Path(None)):
+def get_path_param_id(item_id: Optional[str] = Path(None)):
     return item_id
 
 
@@ -160,7 +161,7 @@ def get_query_type(query: int):
 
 
 @app.get("/query/int/optional")
-def get_query_type_optional(query: int = None):
+def get_query_type_optional(query: Optional[int] = None):
     if query is None:
         return "foo bar"
     return f"foo bar {query}"
diff --git a/tests/test_callable_endpoint.py b/tests/test_callable_endpoint.py
index 8aaf448849..1882e9053a 100644
--- a/tests/test_callable_endpoint.py
+++ b/tests/test_callable_endpoint.py
@@ -1,10 +1,11 @@
 from functools import partial
+from typing import Optional
 
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
 
-def main(some_arg, q: str = None):
+def main(some_arg, q: Optional[str] = None):
     return {"some_arg": some_arg, "q": q}
 
 
diff --git a/tests/test_dependency_overrides.py b/tests/test_dependency_overrides.py
index 3cee6f8ad8..8bb307971b 100644
--- a/tests/test_dependency_overrides.py
+++ b/tests/test_dependency_overrides.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 import pytest
 from fastapi import APIRouter, Depends, FastAPI
 from fastapi.testclient import TestClient
@@ -36,7 +38,7 @@ app.include_router(router)
 client = TestClient(app)
 
 
-async def overrider_dependency_simple(q: str = None):
+async def overrider_dependency_simple(q: Optional[str] = None):
     return {"q": q, "skip": 5, "limit": 10}
 
 
diff --git a/tests/test_extra_routes.py b/tests/test_extra_routes.py
index a2459b3588..6aba3e8dda 100644
--- a/tests/test_extra_routes.py
+++ b/tests/test_extra_routes.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from fastapi.responses import JSONResponse
 from fastapi.testclient import TestClient
@@ -8,7 +10,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    price: float = None
+    price: Optional[float] = None
 
 
 @app.api_route("/items/{item_id}", methods=["GET"])
diff --git a/tests/test_filter_pydantic_sub_model.py b/tests/test_filter_pydantic_sub_model.py
index 9ce753d1e2..90a3729763 100644
--- a/tests/test_filter_pydantic_sub_model.py
+++ b/tests/test_filter_pydantic_sub_model.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 import pytest
 from fastapi import Depends, FastAPI
 from fastapi.testclient import TestClient
@@ -16,7 +18,7 @@ class ModelC(ModelB):
 
 class ModelA(BaseModel):
     name: str
-    description: str = None
+    description: Optional[str] = None
     model_b: ModelB
 
     @validator("name")
diff --git a/tests/test_infer_param_optionality.py b/tests/test_infer_param_optionality.py
index 166c3fcc78..5e673d9c4d 100644
--- a/tests/test_infer_param_optionality.py
+++ b/tests/test_infer_param_optionality.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import APIRouter, FastAPI
 from fastapi.testclient import TestClient
 
@@ -19,7 +21,7 @@ def get_user(user_id: str):
 
 
 @item_router.get("/")
-def get_items(user_id: str = None):
+def get_items(user_id: Optional[str] = None):
     if user_id is None:
         return [{"item_id": "i1", "user_id": "u1"}, {"item_id": "i2", "user_id": "u2"}]
     else:
@@ -27,7 +29,7 @@ def get_items(user_id: str = None):
 
 
 @item_router.get("/{item_id}")
-def get_item(item_id: str, user_id: str = None):
+def get_item(item_id: str, user_id: Optional[str] = None):
     if user_id is None:
         return {"item_id": item_id}
     else:
diff --git a/tests/test_invalid_sequence_param.py b/tests/test_invalid_sequence_param.py
index 069337f79b..f00dd7b934 100644
--- a/tests/test_invalid_sequence_param.py
+++ b/tests/test_invalid_sequence_param.py
@@ -1,4 +1,4 @@
-from typing import Dict, List, Tuple
+from typing import Dict, List, Optional, Tuple
 
 import pytest
 from fastapi import FastAPI, Query
@@ -49,5 +49,5 @@ def test_invalid_simple_dict():
             title: str
 
         @app.get("/items/")
-        def read_items(q: dict = Query(None)):
+        def read_items(q: Optional[dict] = Query(None)):
             pass  # pragma: no cover
diff --git a/tests/test_jsonable_encoder.py b/tests/test_jsonable_encoder.py
index d4ae344421..2514edfde9 100644
--- a/tests/test_jsonable_encoder.py
+++ b/tests/test_jsonable_encoder.py
@@ -1,6 +1,7 @@
 from datetime import datetime, timezone
 from enum import Enum
 from pathlib import PurePath, PurePosixPath, PureWindowsPath
+from typing import Optional
 
 import pytest
 from fastapi.encoders import jsonable_encoder
@@ -60,7 +61,7 @@ class RoleEnum(Enum):
 
 
 class ModelWithConfig(BaseModel):
-    role: RoleEnum = None
+    role: Optional[RoleEnum] = None
 
     class Config:
         use_enum_values = True
diff --git a/tests/test_param_class.py b/tests/test_param_class.py
index bbb9eefcc3..c2a9096d47 100644
--- a/tests/test_param_class.py
+++ b/tests/test_param_class.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import FastAPI
 from fastapi.params import Param
 from fastapi.testclient import TestClient
@@ -6,7 +8,7 @@ app = FastAPI()
 
 
 @app.get("/items/")
-def read_items(q: str = Param(None)):
+def read_items(q: Optional[str] = Param(None)):
     return {"q": q}
 
 
diff --git a/tests/test_serialize_response.py b/tests/test_serialize_response.py
index 1ec957177d..31c08f50df 100644
--- a/tests/test_serialize_response.py
+++ b/tests/test_serialize_response.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
@@ -9,7 +9,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    price: float = None
+    price: Optional[float] = None
     owner_ids: List[int] = None
 
 
diff --git a/tests/test_serialize_response_dataclass.py b/tests/test_serialize_response_dataclass.py
index 4bbb0c2c15..ea048127a8 100644
--- a/tests/test_serialize_response_dataclass.py
+++ b/tests/test_serialize_response_dataclass.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
@@ -10,7 +10,7 @@ app = FastAPI()
 @dataclass
 class Item:
     name: str
-    price: float = None
+    price: Optional[float] = None
     owner_ids: List[int] = None
 
 
diff --git a/tests/test_serialize_response_model.py b/tests/test_serialize_response_model.py
index adb7fda344..056e9c4b04 100644
--- a/tests/test_serialize_response_model.py
+++ b/tests/test_serialize_response_model.py
@@ -1,4 +1,4 @@
-from typing import Dict, List
+from typing import Dict, List, Optional
 
 from fastapi import FastAPI
 from pydantic import BaseModel, Field
@@ -9,7 +9,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str = Field(..., alias="aliased_name")
-    price: float = None
+    price: Optional[float] = None
     owner_ids: List[int] = None
 
 
diff --git a/tests/test_skip_defaults.py b/tests/test_skip_defaults.py
index ed84df66c4..e41d1a286c 100644
--- a/tests/test_skip_defaults.py
+++ b/tests/test_skip_defaults.py
@@ -19,7 +19,7 @@ class Model(BaseModel):
 class ModelSubclass(Model):
     y: int
     z: int = 0
-    w: int = None
+    w: Optional[int] = None
 
 
 class ModelDefaults(BaseModel):
diff --git a/tests/test_sub_callbacks.py b/tests/test_sub_callbacks.py
index 3de3cea993..dc0e3424a9 100644
--- a/tests/test_sub_callbacks.py
+++ b/tests/test_sub_callbacks.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 from fastapi import APIRouter, FastAPI
 from fastapi.responses import JSONResponse
 from fastapi.testclient import TestClient
@@ -8,7 +10,7 @@ app = FastAPI()
 
 class Invoice(BaseModel):
     id: str
-    title: str = None
+    title: Optional[str] = None
     customer: str
     total: float
 
@@ -36,7 +38,7 @@ subrouter = APIRouter()
 
 
 @subrouter.post("/invoices/", callbacks=invoices_callback_router.routes)
-def create_invoice(invoice: Invoice, callback_url: HttpUrl = None):
+def create_invoice(invoice: Invoice, callback_url: Optional[HttpUrl] = None):
     """
     Create an invoice.
 
diff --git a/tests/test_tutorial/test_query_params/test_tutorial007.py b/tests/test_tutorial/test_query_params/test_tutorial007.py
deleted file mode 100644
index 335c103a15..0000000000
--- a/tests/test_tutorial/test_query_params/test_tutorial007.py
+++ /dev/null
@@ -1,95 +0,0 @@
-from fastapi.testclient import TestClient
-
-from query_params.tutorial007 import app
-
-client = TestClient(app)
-
-openapi_schema = {
-    "openapi": "3.0.2",
-    "info": {"title": "FastAPI", "version": "0.1.0"},
-    "paths": {
-        "/items/{item_id}": {
-            "get": {
-                "responses": {
-                    "200": {
-                        "description": "Successful Response",
-                        "content": {"application/json": {"schema": {}}},
-                    },
-                    "422": {
-                        "description": "Validation Error",
-                        "content": {
-                            "application/json": {
-                                "schema": {
-                                    "$ref": "#/components/schemas/HTTPValidationError"
-                                }
-                            }
-                        },
-                    },
-                },
-                "summary": "Read User Item",
-                "operationId": "read_user_item_items__item_id__get",
-                "parameters": [
-                    {
-                        "required": True,
-                        "schema": {"title": "Item Id", "type": "string"},
-                        "name": "item_id",
-                        "in": "path",
-                    },
-                    {
-                        "required": False,
-                        "schema": {"title": "Limit", "type": "integer"},
-                        "name": "limit",
-                        "in": "query",
-                    },
-                ],
-            }
-        }
-    },
-    "components": {
-        "schemas": {
-            "ValidationError": {
-                "title": "ValidationError",
-                "required": ["loc", "msg", "type"],
-                "type": "object",
-                "properties": {
-                    "loc": {
-                        "title": "Location",
-                        "type": "array",
-                        "items": {"type": "string"},
-                    },
-                    "msg": {"title": "Message", "type": "string"},
-                    "type": {"title": "Error Type", "type": "string"},
-                },
-            },
-            "HTTPValidationError": {
-                "title": "HTTPValidationError",
-                "type": "object",
-                "properties": {
-                    "detail": {
-                        "title": "Detail",
-                        "type": "array",
-                        "items": {"$ref": "#/components/schemas/ValidationError"},
-                    }
-                },
-            },
-        }
-    },
-}
-
-
-def test_openapi():
-    response = client.get("/openapi.json")
-    assert response.status_code == 200, response.text
-    assert response.json() == openapi_schema
-
-
-def test_read_item():
-    response = client.get("/items/foo")
-    assert response.status_code == 200, response.text
-    assert response.json() == {"item_id": "foo", "limit": None}
-
-
-def test_read_item_query():
-    response = client.get("/items/foo?limit=5")
-    assert response.status_code == 200, response.text
-    assert response.json() == {"item_id": "foo", "limit": 5}
diff --git a/tests/test_tutorial/test_query_params_str_validations/test_tutorial013.py b/tests/test_tutorial/test_query_params_str_validations/test_tutorial013.py
index 7b1eab2b7d..f2293105c9 100644
--- a/tests/test_tutorial/test_query_params_str_validations/test_tutorial013.py
+++ b/tests/test_tutorial/test_query_params_str_validations/test_tutorial013.py
@@ -31,7 +31,12 @@ openapi_schema = {
                 "parameters": [
                     {
                         "required": False,
-                        "schema": {"title": "Q", "type": "array", "items": {}},
+                        "schema": {
+                            "title": "Q",
+                            "type": "array",
+                            "items": {},
+                            "default": [],
+                        },
                         "name": "q",
                         "in": "query",
                     }
@@ -88,4 +93,4 @@ def test_query_no_values():
     url = "/items/"
     response = client.get(url)
     assert response.status_code == 200, response.text
-    assert response.json() == {"q": None}
+    assert response.json() == {"q": []}
diff --git a/tests/test_validate_response.py b/tests/test_validate_response.py
index 25499e8f93..e9a17e542f 100644
--- a/tests/test_validate_response.py
+++ b/tests/test_validate_response.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 import pytest
 from fastapi import FastAPI
@@ -10,7 +10,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    price: float = None
+    price: Optional[float] = None
     owner_ids: List[int] = None
 
 
diff --git a/tests/test_validate_response_dataclass.py b/tests/test_validate_response_dataclass.py
index 9d78f65ec2..1765dcb434 100644
--- a/tests/test_validate_response_dataclass.py
+++ b/tests/test_validate_response_dataclass.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Optional
 
 import pytest
 from fastapi import FastAPI
@@ -12,7 +12,7 @@ app = FastAPI()
 @dataclass
 class Item:
     name: str
-    price: float = None
+    price: Optional[float] = None
     owner_ids: List[int] = None