Goal

Minimising cosmetic differences between standalone looper and DevFund's looper.

What it does

• mypy and flake8 upgraded to take care of issues such as https://github.com/PyCQA/pyflakes/issues/475;
• applies black and flake8 fixes to looper modules and all DevFund's tests;
• copies over most of the mypy-related annotations from the standalone looper into DevFund's:
  
  standalone looper's usage of typing is preferred, e.g. from typing import ... vs import typing;

• contents of looper/tests/__init__.py moved to looper/tests/base.py, to keep it consistent with the standalone version.

Branch

blackify-mypy-looper

Sanity check for accidental changes:

• No changes to models:

$ python manage.py makemigrations --dry-run
No changes detected

• No migrations:

$ python manage.py migrate --plan
Planned operations:
  No planned migration operations.

• Tests are passing
• It's possible to go through checkout locally