          graph.add_edge(1, 4, 4)
          graph.add_edge(2, 1, 6)
          graph.add_edge(3, 2, 7)
          graph.add_edge(3, 4, 8)
          dfs(nodes[0], self.results.add_result)
          assert_equal(str(self.results), "[0, 1, 3, 2, 4, 5]")
  
          print('Success: test_dfs')
  
  
 
</s> remove     "        dfs(nodes[0], self.results.add_result)\n",
 </s> add     "        graph.dfs(nodes[0], self.results.add_result)\n", </s> remove     "        dfs(nodes[0], self.results.add_result)\n",
 </s> add     "        graph.dfs(nodes[0], self.results.add_result)\n", </s> remove         graph = Graph()
 </s> add         graph = GraphDfs() </s> remove     "        graph = Graph()\n",
 </s> add     "        graph = GraphDfs()\n", </s> remove     "        graph = Graph()\n",
 </s> add     "        graph = GraphDfs()\n",
        graph.dfs(nodes[0], self.results.add_result)
          graph.add_edge(1, 4, 4)
          graph.add_edge(2, 1, 6)
          graph.add_edge(3, 2, 7)
          graph.add_edge(3, 4, 8)
        graph.dfs(nodes[0], self.results.add_result)
          assert_equal(str(self.results), "[0, 1, 3, 2, 4, 5]")
  
          print('Success: test_dfs')
  
  
keep keep keep keep replace keep keep keep keep keep
 Move graph dfs to a class 
graphs_trees/graph_dfs/test_dfs.py