Fix flake8-return warnings

[DimitriPapadopoulos]

Summary of changes

Fix flake8-return issues reported by ruff 0.1.9.

Pull Request Checklist

• Changes have tests
• News fragment added in newsfragments/.
  (See documentation for details)

[abravalheri]

Thank you very much @DimitriPapadopoulos .

Should flake8-return be added to the ruff configuration as well after these fixes?

[DimitriPapadopoulos]

Yes, it could be added. Some rules should be disabled though. I have not fixed such issues:

if ...:
    return ...
else:
    return ...

Thanks to the symmetry, I find the above more readable than:

if ...:
    return ...
return ...

It's your call...

[abravalheri]

Thank you very much @DimitriPapadopoulos, let's merge this for now...
Later we can add the flake8-return.

Some rules should be disabled though.

I am not sure about this. I am more keen to keep the linter configuration as dry as possible, ideally just working out of the box.