Fix typing for Strategies files

[daniellepintz]

Proposed refactor

Fix typing for these files:
https://github.com/PyTorchLightning/pytorch-lightning/blob/7eab379da2fdca542849ed4ad313d0851c2271e3/pyproject.toml#L70-L84

Motivation

As part of #7037 we want to add typing to the entire Lightning codebase.

Additional Context

Make sure you do one PR per file.
Start by removing the file from pyproject.toml. To test mypy locally make sure you have it installed and then simply run mypy.

cc @Borda @justusschock @awaelchli @akihironitta @rohitgr7

[alat-rights]

I would love to take this on. If I'm not missing any hidden complexities here, I should be able to get this done by today?

Edit: Might take a little longer 🙃

[awaelchli]

Hello
This is wonderful.

We are targeting to get some refactors and API updates in for the strategies in upcoming Lightning 1.6 release (#11643, #9932). These have priority over typing, but you are welcome to start if you want. I'm only mentioning this because there are likely going to be merge conflicts so please ping us if you need help resolving these.

To start, I suggest to take some easy ones like single_tpu.py, single_device.py, dp, etc.

Thanks for the help
cheers

[alat-rights]

Sounds great, I'll take a look!

Excited to join the community.

All the best

[daniellepintz]

Thanks @alat-rights! Just assigned you the issue

[mathemusician]

Hello! Permission to make a pull request for this? @daniellepintz

[Borda]

Hello! Permission to make a pull request for this? @daniellepintz

you are more then welcome to do it 🎉