Add type hinting to Python API

[mgovers]

See the TODO in

power-grid-model/src/power_grid_model/data_types.py

Line 13 in 81b1f8c

# When we're dropping python 3.8, we should introduce proper NumPy type hinting

Support for Python 3.8 was dropped in #464

[Cbit11]

I'll do it

[mgovers]

Awesome! LMK if you need any help

[mgovers]

@Cbit11 how is it going with the development?

[Jerry-Jinfeng-Guo]

I don't understand this issue yet, what's wrong with this data_types.py document?

[mgovers]

this may already be done in #613 and #648

[mgovers]

this may already be done in #613 and #648

this is actually not entirely true.

• Starting python3.9, we have list[Foo] and set[Foo] instead of List[Foo] and Set[foo], as well as collections.abc.Iterable and collections.abc.Mapping as opposed to typing.Iterable and typing.Mapping.

• Starting python3.10 ( Drop python 3.9 #638 ) , we will have support for TypeVar including bounds https://docs.python.org/3.10/library/typing.html#typing.TypeVar . This will enable us to remove syntax like Union[SingleDataset, Dict[str, SingleComponentData]] and replace it with SingleDataset, where SingleDataset = Dict[ComponentTypeVar, SingleComponentData] and ComponentTypeVar = TypeVar['ComponentTypeVar', bounds=[ComponentType, str]]

• Starting python3.10, Union is deprecated and replaced with the much simpler syntax |