Add Flake8/autoflake to pre-commit

[jthorton]

It might be good to add flake8 to the pre-commit to catch unused imports like here or formatting issues.

[IAlibay]

I've had mixed experiences with unused imports linters in libraries where you often intentionally create an unused import (i.e. to make downstream imports easier or just to keep some kind of backward compatibility).

I'd be happy to support this (especially since those two examples make sense to catch!), but would encourage caution.

[mikemhenry]

I am pro adding it, since in the cases you mentioned @IAlibay you can add # noqa or whatever to have it ignore that line, which I think is a good thing since it makes it really explicit and clear what you are trying to do.

I agree we need to be careful to make sure that we don't remove unused imports that are in fact "used".

ruff might be another tool to look at