Changes from review:

- Fixed second overload of `_TripleType` to return `Path` instead of
  `_PredicateType`.

rdflib/graph.py

@@ -481,7 +481,7 @@ def triples(
     def triples(
         self,
         triple: Tuple[Optional["_SubjectType"], Path, Optional["_ObjectType"]],
-    ) -> Generator[Tuple["_SubjectType", "_PredicateType", "_ObjectType"], None, None]:
+    ) -> Generator[Tuple["_SubjectType", Path, "_ObjectType"], None, None]:
         ...
 
     @overload