✏ add docstring

and fix hit typing

Graph/graph/graph.py

 import itertools
 
-from typing import List, Optional
+from typing import Generator, Optional
 
 
 class NDGraph:
@@ -78,9 +78,16 @@ class Node:
                 return n
 
 
-def DFS(graph: Graph, node: Node) -> List[Node]:
+def DFS(graph: Graph, node: Node) -> Generator[Node]:
     """
-    Depth First Search
+    **D**epth **F**irst **S**earch.
+    We start the path from the node given as argument,
+    This node is labeled as 'visited'
+    The neighbors of this node which have not been already 'visited' nor 'to visit' are labelled as 'to visit'
+    We pick the last element to visit and visit it
+    (The neighbors of this node which have not been already 'visited' nor 'to visit' are labelled as 'to visit').
+    on so on until there no nodes to visit anymore.
+
     :param graph:
     :param node:
     :return:
@@ -95,10 +102,16 @@ def DFS(graph: Graph, node: Node) -> List[Node]:
         yield n
 
 
-def BFS(graph: Graph, node: Node) -> List[Node]:
+def BFS(graph: Graph, node: Node) -> Generator[Node]:
     """
-    Breadth First search
-    
+    **B**readth **F**irst **s**earch
+    We start the path from the node given as argument,
+    This node is labeled as 'visited'
+    The neighbors of this node which have not been already 'visited' nor 'to visit' are labelled as 'to visit'
+    we pick the **first** element of the nodes to visit and visit it.
+    (The neighbors of this node which have not been already 'visited' nor 'to visit' are labelled as 'to visit')
+    on so on until there no nodes to visit anymore.
+
     :param graph:
     :param node:
     :return: