Fix potential bug in has edge

Xuefeng-Zhu · Xuefeng-Zhu · commit 9b707a06026c · 2015-05-10T23:50:41.000-05:00
The u node may not exist.
diff --git a/graphs/graph.py b/graphs/graph.py
@@ -69,9 +69,7 @@ def has_edge(self, edge):
         graph. An edge, here, is a pair of node like C(m, n) or a tuple
         """
         u, v = edge
-        if v not in self.node_neighbors[u]:
-            return False
-        return True
+        return v in self.node_neighbors.get(u, [])
 
     def neighbors(self, node):
         """
