      }
     ],
     "source": [
      "%%writefile graph.py\n",
      "from collections import OrderedDict\n",
      "from enum import Enum  # Python 2 users: Run pip install enum34\n",
      "\n",
      "\n",
      "class State(Enum):\n",
      "    unvisited = 1\n",
 
</s> remove     "    unvisited = 1\n",
 </s> add     "    unvisited = 0\n",
    "    visiting = 1\n", </s> remove from collections import OrderedDict
 </s> add  </s> remove     unvisited = 1
 </s> add     unvisited = 0
    visiting = 1 </s> remove     "from collections import OrderedDict\n",
    "\n",
    "\n",
 </s> add  </s> remove     "    visiting = 3\n",
 </s> add 
      }
     ],
     "source": [
      "%%writefile graph.py\n",

      "from enum import Enum  # Python 2 users: Run pip install enum34\n",
      "\n",
      "\n",
      "class State(Enum):\n",
      "    unvisited = 1\n",
keep keep keep keep replace keep keep keep keep keep
 Rework graph challenge and solution (#86) 
graphs_trees/graph/graph_solution.ipynb