Add DivIcon and CustomIcon as accepted type of Marker icon

[pixelsapphire]

A DivIcon works when passed as the icon argument of Marker, but the argument is annotated as Optional[Icon] instead of Optional[Union[Icon, "DivIcon"]].

[Conengmo]

Hi @pixelsapphire, thanks for your PR, that makes sense! Good to improve this.

It's missing an import of that class, can you maybe add that? It will lead to a circular import, so the way to address that is by only importing it for type checking:

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from folium.features import DivIcon

One more thing: I assume this argument also accepts CustomIcon objects. Maybe you can add that as well?

Thanks for your help!

[pixelsapphire]

It's missing an import of that class

My bad, should have checked that first.

I assume this argument also accepts CustomIcon objects. Maybe you can add that as well?

Done and dusted.

[hansthen]

@Conengmo Do you know what is the issue with the failing mypy checks? It seems mypy is bothered by some method signature redefinitions between Branca and Folium.

[pixelsapphire]

@hansthen This is something I've been wondering about too. Why does the render method in Folium classes return None, when this method in Branca classes (and in the Element class itself) returns str?

[Conengmo]

I'm trying to reproduce this issue locally...

When I upgrade my local packages I get the same issue. It also occurs on the main branch.

The change in this PR doesn't cause the issue, and also doesn't add any type issues (the number of issues on this PR and the main branch is the same).

I'll work on fixing the issues in a separate PR.

Means we can go ahead and merge this PR!

[Conengmo]

Thanks @pixelsapphire! This PS is much appreciated, I hadn't noticed this!

[hansthen]

@hansthen This is something I've been wondering about too. Why does the render method in Folium classes return None, when this method in Branca classes (and in the Element class itself) returns str?

I have been banging my head on this for a few days now. The signature redefinition seems to start already in Branca. See brana.element.Figure for instance. The children are void rendered (without actually returning anything). Then the _template of Figure is rendered. This will render just the header, html and script attributes and return the result.

    def render(self, **kwargs):
        """Renders the HTML representation of the element."""
        for name, child in self._children.items():
            child.render(**kwargs)
        return self._template.render(this=self, kwargs=kwargs)

In branca.element.MacroElement, the children are also void rendered, but here the render method itself also has a void signature.

I will open a discussion on the talk page for this.