Support fuller files kwarg for requests.post

[semperos]

Thanks for taking the time to review this! I ran into this type mismatch with some code that leverages the requests library and was hoping to update responses to match.

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The files keyword argument for the requests.post function has this type:

files: _Files | None = ...

This commit adds this type alias as found in requests version 2.32.2 and updates this library's multipart_matcher function's files keyword argument to be of type _Files.

[beliaev-maksim]

should we just import it from requests then ?

[markstory]

should we just import it from requests then ?

:+1: to importing the types if we can.

[semperos]

I neglected to run tox before pushing that last commit, there are errors; I'll fix them before pushing again, no need to approve the workflows.

[semperos]

I believe Python's import prevents importing names with a leading underscore; I get an ImportError: cannot import name '_Files' from 'requests.sessions' when I attempt to from requests.sessions import _Files.

Two paths forward that I see:

1. Ask the requests maintainers to expose this type.
2. Recreate the types here.

The original PR workflow run showed that the syntax I ported from requests of tuple[_FileName, _FileContent] breaks in Python 3.8. If we go with option 2, I can adjust the type syntax to make the code compatible with Python 3.8.

[beliaev-maksim]

can you please send a permalink to the piece of code at requests where they define the type?

[semperos]

Apologies for not double-checking the source of the types, I had jumped to them in my editor and didn't realize they weren't provided by the requests implementation itself. The types I included in my first commit were from typeshed.

Here is the permalink to where _Files is used: https://github.com/python/typeshed/blob/7cae61f61a042a772010274dd1d8f1ee4454e5a4/stubs/requests/requests/sessions.pyi#L148

Here is the permalink to the definition of _Files itself: https://github.com/python/typeshed/blob/7cae61f61a042a772010274dd1d8f1ee4454e5a4/stubs/requests/requests/sessions.pyi#L92

[beliaev-maksim]

so, if we add a dependency and import the type, will it work?