The code is pulled almost unchanged from typing_extensions:

• decorator implementation
• tests

Question that came up was where to put the type variable and what to name it:

• In typing_extensions the type variables use underscore prefixes to indicate that they are not public, but typing doesn't appear to use that convention so I named the type variable F.
• I couldn't put the type variable next to all of the other ones (used in generic container definitions) because it relies on Callable which is defined below. If this is a problem I could correct it using a forward reference, or we could try to rearrange the module to put special forms above type variables.

Testing the code:

First set up the repo, following instructions
at https://devguide.python.org/ by running:

./configure --with-pydebug && make -j

Then run the typing tests:

./python -m test test_typing -v

I ran the full test suite with

./python -m test -j3

and it came back clean except for a test_grp failure which I seem to get on trunk as well - likely something in my build is misconfigured but I'm pretty sure it is unrelated to the changes here.

• Issue: Add typing.override decorator #101561

Make sure the docs build:

cd Doc
make venv
make html