Code improvements
When I started the process, the IntelliJ "Default Inspection" produced 4 errors, 568 warnings and 879 weak warnings. After this MR, we are down to no errors, 338 warnings and 860 weak warnings. Clearly a ways to go.
- Remove unused imports (the rest)
- Fix errors in docstrings
- Replace
Response(status=...)
withResponse(status_code=...)
which is more correct.