Add automatic checks for static typing about data-describe

[truongc2]

Are these checks added to the unit test or the source code?

[terrytangyuan]

At least should be added to sanity checks prior to unit tests using tools like mypy. Adding types to source code may not be necessary yet.

[truongc2]

I'm new to static typing so I'm having trouble understanding where the checks should be located. If not in the source code, then would it be added to the unit testing code? Or is this an entirely new file?

[terrytangyuan]

@truongc2 mypy has CLI and you can use it together with flake8: https://github.com/ambv/flake8-mypy.

https://github.com/python/mypy#ide-linter-integrations-and-pre-commit

[dvdjlaw]

More info for @truongc2:
Make sure you have installed pre-commit in your local dev environment

1. Update .pre-commit-config.yaml to include mypy checks in addition to flake8 (which is already added).
2. Decide how mypy should be configured (args), See https://github.com/pre-commit/mirrors-mypy
3. Test/run locally to ensure the mypy checks run and resolve any possible issues
4. Merge to integrate with CI (Github Actions). Pre-commit is already implemented so there shouldn't be any additional change to activate