Add architectural metrics for python

[swsms]

Hyperstyle uses SpringLint to evaluate architectural metrics for Java (e.g. Coupling, Cohesion).
It is a good idea to do the same (or even more) for Python.

There are several suitable linters to try:

• Django Lint: https://github.com/lamby/django-lint
• Searching for dead code https://wemake-python-stylegui.de/en/latest/ [By Nikita Sobolev]
• Evaluate cohesion: https://github.com/mschwager/cohesion
• Different metrics: https://github.com/rubik/radon

New ideas are also welcome in the comments.