Reducing mypy bypasses

[edan-bainglass]

I recently added a mypy hook to our pre-commit script and conformed the codebase to it (#27). However, several errors had to be silenced, as their reasons required better understanding of the code. Such issues are documented below. I'll address them over time. Assistance welcomed :)

[edan-bainglass]

The CyclingParameter model assigns default Nones to the value and default_value parameters. mypy raises an issue, as these are of type DataT. Solving the issue by wrapping DataT with Optional breaks the code. This is because the build_parameter_widget function in technique_widget.py runs a type check on the value parameter and raises an error if it is not str. Not yet sure of the purpose of this check.

[edan-bainglass]

Several models in cycling.py receive an extra inheritance. What is this? mypy does not approve of adding this, though it is a supported feature apparently.

[edan-bainglass]

The Optional and extra issues have been addressed in #31.

[edan-bainglass]

The last mypy bypass relates to the use of global variables in query.py. Discarding the global variables will require some refactoring. Will need to think about how to best approach it. Soon...