code style should pass flake8

[prjemian]

All code modules should be made to pass flake8, then add code style (flake8) testing to the CI (github workflow). The command tool black -l 75 can be used to reformat files to become compliant. Since black is agressive about styling, there may be some sections that should be excluded from the formatting (yet these sections must still pass flake8).

    # this line will be checked by black
    data = [1,2,3]

    # this line will not be checked by black
    # fmt: off
    a = data[-1]
    # fmt: off

    # this line will be checked by black
    b = data[:2]

@gfabbris: You were interested in this feature of black