      "    * Yes\n",
      "* Can we assume we already have a Node class with an insert method?\n",
      "    * Yes"
     ]
    },
    {
     "cell_type": "markdown",
 
</s> remove       "Writing height.py\n"
 </s> add       "Overwriting height.py\n" </s> remove     "version": 2
 </s> add     "version": 3 </s> remove     "version": 2
 </s> add     "version": 3 </s> remove    "display_name": "Python 2",
 </s> add    "display_name": "Python 3",
    "    * Yes\n",
    "* Can we assume this fits memory?\n",
      "    * Yes\n",
      "* Can we assume we already have a Node class with an insert method?\n",
    "    * Yes\n",
    "* Can we assume this fits memory?\n",
      "    * Yes"
     ]
    },
    {
     "cell_type": "markdown",
keep add keep keep keep keep keep
 Update constraints for tree height challenge and solution (#87) 
graphs_trees/tree_height/height_solution.ipynb