Improvements for rustworkx.visit annotations (Qiskit#1362)

* Improvements for rustworkx.visit annotations

* Black

* Remove double import sys

* Add overloads

* Another fix

* Revert "Add overloads"

This reverts commit 499ea56.

* Revert visitor defaults

Author: IvanIsCoding

rustworkx/rustworkx.pyi

@@ -31,9 +31,6 @@ from collections.abc import (
 from abc import ABC
 from rustworkx import generators  # noqa
 
-# from collections.abc import Sequence as SequenceCollection
-from typing_extensions import Self
-
 import numpy as np
 import numpy.typing as npt
 import sys
@@ -43,6 +40,11 @@ if sys.version_info >= (3, 13):
 else:
     from typing_extensions import TypeVar
 
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
+
 _S = TypeVar("_S", default=Any)
 _T = TypeVar("_T", default=Any)
 
@@ -975,9 +977,9 @@ def graph_transitivity(graph: PyGraph, /) -> float: ...
 
 # Traversal
 
-_BFSVisitor = TypeVar("_BFSVisitor", bound=BFSVisitor)
-_DFSVisitor = TypeVar("_DFSVisitor", bound=DFSVisitor)
-_DijkstraVisitor = TypeVar("_DijkstraVisitor", bound=DijkstraVisitor)
+_BFSVisitor = TypeVar("_BFSVisitor", bound=BFSVisitor, default=BFSVisitor)
+_DFSVisitor = TypeVar("_DFSVisitor", bound=DFSVisitor, default=DFSVisitor)
+_DijkstraVisitor = TypeVar("_DijkstraVisitor", bound=DijkstraVisitor, default=DijkstraVisitor)
 
 def digraph_bfs_search(
     graph: PyDiGraph,

rustworkx/visit.pyi

@@ -9,12 +9,19 @@
 # This file contains only type annotations for PyO3 functions and classes
 # For implementation details, see visit.py
 
-from typing import Any, Generic, TypeVar
+from typing import Any, Generic
+
+import sys
+
+if sys.version_info >= (3, 13):
+    from typing import TypeVar
+else:
+    from typing_extensions import TypeVar
 
 class StopSearch(Exception): ...
 class PruneSearch(Exception): ...
 
-_T = TypeVar("_T")
+_T = TypeVar("_T", default=Any)
 
 class BFSVisitor(Generic[_T]):
     def discover_vertex(self, v: int) -> Any: ...