      "    test = TestGraph()\n",
      "    test.test_graph()\n",
      "\n",
      "\n",
      "if __name__ == '__main__':\n",
      "    main()"
     ]
    },
 
</s> remove     "    visiting = 3\n",
 </s> add  </s> remove     "        self.adjacent = OrderedDict()  # key = node, val = weight\n",
 </s> add     "        self.adjacent = {}  # key = node, val = weight\n",
    "    test.test_graph_undirected()\n",
      "    test = TestGraph()\n",
      "    test.test_graph()\n",
    "    test.test_graph_undirected()\n",
      "\n",
      "\n",
      "if __name__ == '__main__':\n",
      "    main()"
     ]
    },
keep add keep keep keep keep keep keep
 Rework graph challenge and solution (#86) 
graphs_trees/graph/graph_challenge.ipynb