* Ignore Flake8 unused import error F401
https://flake8.readthedocs.io/en/latest/user/error-codes.html
The apparently unused imports may be needed for SQLAlchemy.
As the code comment says:
make sure all SQL Alchemy models are imported before initializing DB
otherwise, SQL Alchemy might fail to initialize properly relationships
See GitHub 28 and 29
* Ignore Flake8 unused variable error F841
https://flake8.readthedocs.io/en/latest/user/error-codes.html
The apparently unused variables may be needed for tests.
* Bring line length into compliance with Black
Should be 88 characters.
* Format alembic code with Black
