This part is pretty normal, most of the code is probably already familiar to you:
-```Python hl_lines="10-14 37-54"
+```Python hl_lines="9-13 36-53"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```
First create a new `APIRouter` that will contain one or more callbacks.
-```Python hl_lines="5 26"
+```Python hl_lines="3 25"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```
* 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="17-19 22-23 29-33"
+```Python hl_lines="16-18 21-22 28-32"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```
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="36"
+```Python hl_lines="35"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```