allow to add property to an edge

Graph/graph/graph_3.py

@@ -51,6 +51,9 @@ class Edge:
         """the edge properties"""
         return {k: v for k, v in self.__dict__.items()}
 
+    def __setitem__(self, key, value):
+        setattr(self, key, value)
+
 
 class Graph(metaclass=ABCMeta):
     """
@@ -98,6 +101,13 @@ class Graph(metaclass=ABCMeta):
             yield n
 
 
+    def get_node_by_id(self, node_id):
+        nodes = self._nodes.keys()
+        for n in nodes:
+            if n.id == node_id:
+                return n
+
+
     def nodes(self) -> Iterator[Node]:
         """
         Iterates over all nodes belonging to the graph