🐛 fix typing

Graph/graph/graph.py

 import itertools
 
-from typing import Generator, Optional
+from typing import Iterator, Optional
 
 
 class NDGraph:
@@ -78,7 +78,7 @@ class Node:
                 return n
 
 
-def DFS(graph: Graph, node: Node) -> Generator[Node]:
+def DFS(graph: NDGraph, node: Node) -> Iterator[Node]:
     """
     **D**epth **F**irst **S**earch.
     We start the path from the node given as argument,
@@ -102,7 +102,7 @@ def DFS(graph: Graph, node: Node) -> Generator[Node]:
         yield n
 
 
-def BFS(graph: Graph, node: Node) -> Generator[Node]:
+def BFS(graph: NDGraph, node: Node) -> Iterator[Node]:
     """
     **B**readth **F**irst **s**earch
     We start the path from the node given as argument,