Less clumsy implementation of has_edge_id.

topydo/lib/Graph.py

@@ -141,8 +141,7 @@ class DirectedGraph(object):
         """
         Returns True if the client registered an edge with the given id.
         """
-        l = [e for e in self._edge_numbers.itervalues() if e == p_id]
-        return len(l) > 0
+        return p_id in self._edge_numbers.values()
 
     def edge_id(self, p_from, p_to):
         """