Add type annotation docs for PyGraph

README.md

@@ -23,6 +23,7 @@ All graph classes and top-level functions are accessible with a single import.
 To illustrate this, the following example calculates the shortest path
 between two nodes `A` and `C` in an undirected graph.
 
+
 ```python3
 import rustworkx
 
@@ -40,8 +41,13 @@ graph.add_edges_from([(a, b, 1.5), (a, c, 5.0), (b, c, 2.5)])
 
 # Returns the path A -> B -> C
 rustworkx.dijkstra_shortest_paths(graph, a, c, weight_fn=float)
+
 ```
 
+NOTE:The library supports standard Python type annotations (e.g., `PyGraph[NodeData, EdgeData]`) for specifying expected data types.
+
+
+
 ## Installing rustworkx
 
 rustworkx is published on [PyPI](https://pypi.org/project/rustworkx/) so on x86\_64, i686, ppc64le, s390x, and

src/digraph.rs

@@ -170,6 +170,31 @@ use super::dag_algo::is_directed_acyclic_graph;
 /// :math:`2^{32} - 1` (4,294,967,294) each. Attempting to add more nodes or
 /// edges than this will result in an exception being raised.
 ///
+/// Type Annotations:
+///
+/// You may use standard Python typing for specifying expected data types for  node and edge parameters.
+/// The generic parameters for ``PyDiGraph`` are ordered like this: ``PyDiGraph[NodeData, EdgeData]``.
+///
+/// .. code-block:: python
+///
+///     import rustworkx as rx
+///
+///     graph: rx.PyDiGraph[str, int] = rx.PyDiGraph()
+///     node_a = graph.add_node("qubit0")
+///     node_b = graph.add_node("qubit1")
+///     graph.add_edge(node_a, node_b, 10)
+///
+/// If you use methods that create edges without data (that is ,connecting 2 nodes with an edge with no value), such as
+/// :meth:`~rustworkx.PyDiGraph.add_edges_from_no_data`, you must include
+/// ``None`` in your edge (``_T``) type annotation (using ``| None``).
+///
+/// .. code-block:: python
+///
+///     # Type hinting a graph where edges can be created without a value
+///     graph: rx.PyDiGraph[str, int | None] = rx.PyDiGraph()
+///     graph.add_nodes_from(["qubit0", "qubit1"])
+///     graph.add_edges_from_no_data([(0, 1)])  # parent=0, child=1
+///
 /// :param bool check_cycle: When this is set to ``True`` the created
 ///     ``PyDiGraph`` has runtime cycle detection enabled.
 /// :param bool multigraph: When this is set to ``False`` the created

src/graph.rs

@@ -132,6 +132,31 @@ use petgraph::visit::{
 /// :math:`2^{32} - 1` (4,294,967,294) each. Attempting to add more nodes or
 /// edges than this will result in an exception being raised.
 ///
+/// Type Annotations:
+///
+/// You can use standard Python typing for specifying expected data types for both node and edge parameters.
+/// The generic parameters for ``PyGraph`` are ordered as ``PyGraph[NodeData, EdgeData]``.
+///
+/// .. code-block:: python
+///
+///     import rustworkx as rx
+///
+///     graph: rx.PyGraph[str, int] = rx.PyGraph()
+///     node_a = graph.add_node("qubit0")
+///     node_b = graph.add_node("qubit1")
+///     graph.add_edge(node_a, node_b, 10)
+///
+/// If you plan to use methods that create edges without data (connecting 2 nodes with an edge with no value), such as
+/// :meth:`~rustworkx.PyGraph.add_edges_from_no_data`, you must include
+/// ``None`` in your edge (_T) type annotation (using ``| None``).
+///
+/// .. code-block:: python
+///
+///     # Type hinting a graph where edges can be created without a value
+///     graph: rx.PyGraph[str, int | None] = rx.PyGraph()
+///     graph.add_nodes_from(["qubit0", "qubit1"])
+///     graph.add_edges_from_no_data([(0, 1)])
+///
 /// :param bool multigraph: When this is set to ``False`` the created PyGraph
 ///     object will not be a multigraph. When ``False`` if a method call is
 ///     made that would add parallel edges the weight/weight from that