Run black and flake8 formatting on all files

[flabbamann]

We have pre-commit hooks for black and flake8 but the python files are not (yet) formatted correctly.

The purpose of this PR is to format all files with pre-commit run --all-files to avoid code changes in other PRs get buried in a lot of formatting changes.

We could also run pre-commit in the actions pipeline to ensure all PRs are formatted correctly. Additionally I suggest adding isort to organise the imports automatically.

Please merge #74 first

[hthiery]

thank you