Support type hinting

[q-wertz]

Is your feature request related to a problem? Please describe.
Currently type hinting is not supported by folium. Are there any plans to implement this?

Describe the solution you'd like
Typing in folium and type hints for the public interfaces (Maybe autogenerated)

Describe alternatives you've considered
Excluding folium in my personal project from type checking by mypy

Additional context
None

Implementation
folium is maintained by volunteers. Can you help make a PR if we want to implement this feature?
-> Can try to help with this

[Conengmo]

Yes, that would be nice. Though type hints in folium are not that useful, since we use a lot of duck-typing. I was working on a change a while back: #1297

[q-wertz]

Ah sorry, didn't see the PR only searched the issues.

Is it not merged due to a certain reason or just not finished?

[Conengmo]

Just not finished. I think we could finish it this time around.

[q-wertz]

If you need testing or something I can help with let me know

[q-wertz]

After updating folium to 0.15.0 mypy still says:

plots.py:11: error: Skipping analyzing "folium": module is installed, but missing library stubs or py.typed marker  [import-untyped]
plots.py:11: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports

Not a pro in this, but I think you need to add an (empty) py.typed file in the folium folder. (At least mypy stops giving the error message as soon as I add it manually in my venv folium lib...