I don't object to it, but if you want to land this you'll need to do it in a backwards-compatible fashion (so the old names work but raise a warning)

I've used PEP 562 idea here, but as it was introduced in 3.7, so I added the backport implementation for 3.6 as requirement. I can also copy the file if you wish so, and we don't add it as dependency.

I've also added tests to check that the warning is being raised on the wanted types.

I'd rather just do it the "old fashioned" way if we could - expose them as actual top-level module objects rather than bringing in extra code just for this.

I'm not following you. 🤔 How am I supposed to warn the user about the deprecation at import time without this implementation?

Or you just meant to not use __all__ and __deprecated__?

Oh, I forgot they were type classes for a second, sorry. Thought they were actual classes where you could do it with a mixin on instantiation.

In that case, let's vendor pep562 in provided the license matches - I don't want more dependencies!

There's a mismatch between the formatters, isort and black are reformatting themselves on the pre-commit 🤔

EDIT: black has by default 88 line length, but flake8 and isort are configured to have 119. On the pre-commit, isort runs and formats the code to 119, then black reformats back to 88. 😅

If I apply either configuration, I'll have a lot more diffs here... Should I open another PR to fix this mismatch, and which one do you prefer, 88 or 119?

EDIT2: The problem is with this big import:

from typing import (
    Any,
    Awaitable,
    Callable,
    Dict,
    Iterable,
    List,
    Optional,
    Tuple,
    Type,
    Union,
)

Which isort says it should be in the same line, and black says it should not. 😅

Notes about the changes:

• I've added pep562 as private module, so we can remove easily by the 3.6 EOL.
• I've removed all the unnecessary code on _pep562.py (and tried to modify the less I could, jfyk).

I think sticking with black's default length of 88 is the best approach - let's handle that in a separate PR. I'll merge this in now so we can avoid mixing linting in here - I think it looks good now, so thanks for bearing with my requests!

Thank you! 🎉