As per the comments, this mirrors the [datetime documentation](https://docs.python.org/3/library/datetime.html#datetime.datetime.fromtimestamp).
```
>>> import time
>>> time.localtime(
999999999999999999999)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OverflowError: timestamp out of range for platform time_t
>>> time.localtime(-3600)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OSError: [Errno 22] Invalid argument
```
:const:`None`, the current time as returned by :func:`.time` is used. The dst
flag is set to ``1`` when DST applies to the given time.
+ :func:`localtime` may raise :exc:`OverflowError`, if the timestamp is
+ outside the range of values supported by the platform C :c:func:`localtime`
+ or :c:func:`gmtime` functions, and :exc:`OSError` on :c:func:`localtime` or
+ :c:func:`gmtime` failure. It's common for this to be restricted to years
+ between 1970 and 2038.
+
.. function:: mktime(t)