Use of type hints in NLmod

[rubencalje]

So @martinvonk has been adding type hints to NLmod, which make the use of the code easier. More documentation is probably better, but it does make the code more bulky. I think we should use type hints everywhere or nowhere in NLmod, to maintain some unity within NLmod. But I am curious what others think.

[dbrakenhoff]

I like type hints where it really helps to make it clearer what the input should be, e.g. for options especially or for functions where it isn't as clear. I don't think it's really necessary where the argument name makes it really clear what it expects. But doing it halfway is also weird, so I think my vote is yes on type hinting. But I also don't feel like adding it everywhere all at once, so slowly over time is fine by me.

So big fan of this:

def func(da: xr.DataArray | np.ndarray, method: Literal['simple_method', 'some_other_method']) -> xr.DataArray:

This i don't think is very necessary to make things clearer, and does add a bit a of clutter. But on the whole, I'm fine with this clutter if it makes stuff more clear in the ambiguous cases.

def func(ax: plt.Axes)

And I think we need to define some of our own complex types that we allow for our functions e.g. Series | DataFrame, XarrayDataObject = DataArray | Dataset, ArrayLike = np.ndarray | DataArray, ModelLike = Dataset | fp.mf6.Modflowgwf.

[martinvonk]

I really like type hinting as you have noticed :)
Especially since we don't have to support python 3.9 any more. This makes the imports much cleaner. So no more:

from typing import Union, List
A: List[Union[int, str]]= [1,"b"]

but just clean python code:

A: list[int | str] = [1, "b"]

I'm against type checking with MyPy for NLmod. That makes life way too difficult, especially when using other packages that aren't properly typed. But to use type hints as a form of extra documentation/readability sounds great to me.

[OnnoEbbens]

I am not a fan of type hints, for me it is just an extra effort for which I don't see enough benefits. But to be honest I have not used them yet so maybe I am missing out on something. Therefore if you are in favor I am willing to use them.