Update app.py

app.py

@@ -48,7 +48,7 @@ def display_tsp():
                 dist = dist
                 G.add_edge(i, j, weight=dist)
 
-        cycle = nx_app.christofides(G, weight="weight")
+        cycle = nx.christofides(G, weight="weight")
         edge_list = list(nx.utils.pairwise(cycle))
 
         # Draw closest edges on each node only