mypy checks fail on case-insensitive filesystem

[SteVwonder]

The case insensitivity means that an unintentional alias is created for the Job class since psi/j/Job.py and psi/j/job.py seemingly both exist.

(.venv-vscode-focal)  fluxuser@1f7fe27de5f4:/workspaces/psi-j-python$ make typecheck
mypy --config-file=.mypy --strict src tests
src/psi/j/Job.py:117: error: Argument 1 to "cancel" of "JobExecutor" has incompatible type "psi.j.Job.Job"; expected "psi.j.job.Job"
(.venv-vscode-focal)  fluxuser@1f7fe27de5f4:/workspaces/psi-j-python$ mypy --version
mypy 0.910

The impact here is that mypy checks will fail on any mac that has a case insensitive filesystem and windows machines. I also suspect that runtime can be impacted by this (e.g., import psi.j.Job - should that import the "Job.py" file or the Job class exposed by psi.j).

[SteVwonder]

Two solutions that I'm aware of would be to either rename the Job class or rename psi/j/job.py to something else, maybe psi/j/job_class.py. If we rename the file, you can still import/reference the Job class as psi.j.Job since the psi/j/init.py exports it.

[hategan]

There appear to be issues in general with python imports and mypy when running on code that is on case-insensitive file systems. Since the type correctness of the psi/j code can be verified on other systems, I do not believe that we gain much by adding workarounds to actual bugs (or regressions; see python/mypy#1961) in mypy.