      "\n",
      "\n",
      "class State(Enum):\n",
      "    unvisited = 0\n",
      "    visiting = 1\n",
      "    visited = 2\n",
      "\n",
      "\n",
      "class Node:\n",
 
</s> remove     "        return self._create_min_bst(array, 0, len(array)-1)\n",
 </s> add     "        return self._create_min_bst(array, 0, len(array) - 1)\n", </s> remove     "        node.left = self._create_min_bst(array, start, mid-1)\n",
    "        node.right = self._create_min_bst(array, mid+1, end)\n",
 </s> add     "        node.left = self._create_min_bst(array, start, mid - 1)\n",
    "        node.right = self._create_min_bst(array, mid + 1, end)\n", </s> remove     "    * hanoi(n-1, src, buffer)\n",
 </s> add     "    * hanoi(n-1, src, buffer, dest)\n", </s> remove     "    * hanoi(n-1, buffer, dest)    \n",
 </s> add     "    * hanoi(n-1, buffer, dest, src)\n",
    "\n",
      "\n",
      "\n",
      "class State(Enum):\n",
    "\n",
      "    unvisited = 0\n",
      "    visiting = 1\n",
      "    visited = 2\n",
      "\n",
      "\n",
      "class Node:\n",
keep keep add keep keep keep keep keep keep
 Update formatting and whitespace in a few challenges (#142) 
graphs_trees/graph/graph_challenge.ipynb