pamhyr: Minor change.

src/Model/Network/Graph.py

@@ -67,9 +67,8 @@ class Graph(object):
 
     def add_edge(self, n1:Node, n2:Node):
         # This edge already exists ?
-        if list(filter(lambda e: (e.node1 == n1 and
-                                  e.node2 == n2),
-                       self._edges)):
+        if any(filter(lambda e: (e.node1 == n1 and e.node2 == n2),
+                      self._edges)):
             return None
 
         edge = Edge(self._edges_ids, "", n1, n2)