Document how to use basic type annotations with `PyGraph`

[johnthagen]

What is the expected enhancement?

I find being able to statically type the generic Graph() from NetworkX to be a very useful feature for maintainability and self-documentation for other developers. Could we add some very simple docs so that if someone searching "typing" or similar in the user guide they are brought to a short example that documents how to type a PyGraph with its node and edge types? It took me a while of digging through issues to learn that typing the generic types was supported.

For example, it's not immediately clear to me without digging through the source code what the order of the generic parameters to PyGraph[Any, Any] are.

I think this would also make the feature more discoverable for new users.

[johnthagen]

For anyone else who finds this, looking here

https://github.com/Qiskit/rustworkx/blob/76d3c15f101af832074e0c3864d41d9423e37e83/rustworkx/rustworkx.pyi#L1303C1-L1303C32

class PyGraph(Generic[_S, _T]):
    ...
    def add_edge(self, node_a: int, node_b: int, edge: _T, /) -> int: ...
    ...
    def add_node(self, obj: _S, /) -> int: ...

So it's PyGraph[NodeType, EdgeType]

Another thing I learned through using this is that if you use PyGraph.add_edges_from_no_data(), you need to add | None to your _T edge type.

[IvanIsCoding]

I will post a more detailed reply later, but yes documentation is welcome! And PyGraph.add_edges_from_no_data was one of the few tricks we had to do to prevent many methods from returning T | None which would have been less useful