Deprecation warnings in 3.8

[wumpus]

/home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/aiohttp/multipart.py:8: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working
from collections import Mapping, Sequence, deque

This is a safe change to make, collections.abc was introduced in 3.3.

[asvetlov]

GitMate.io thinks possibly related issues are #3252 (False-positive deprecation warning for partial async handlers), #1575 (Deprecation policy), #130 (Multiple Test Warnings on Python 3.4 (ResourceWarning / DeprecationWarning)), #2670 ([injection] 2.3.8 broke certain regex match patterns), and #1603 (1.3 Release).

[augustogoulart]

I'm getting the same warnings while writing tests for an application using Python 3.7 and pytest 3.8.0.
@wumpus do you have plans to work on that? If not, I would like to work on a patch for it. Thanks.

[wumpus]

Please do the patch! It's quite easy.

[Harmon758]

This specific line should already be fixed with #3258 (c8c0567).

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a [new issue] for related bugs.
If you feel like there's important points made in this discussion, please include those exceprts into that [new issue].
[new issue]: https://github.com/aio-libs/aiohttp/issues/new