      "def in_order_traversal(node, visit_func):\n",
      "    # TODO: Implement me\n",
      "    pass\n",
      "\n",
      "def pre_order_traversal(node, visit_func):\n",
      "    # TODO: Implement me\n",
      "    pass\n",
      "\n",
      "def post_order_traversal(node, visit_func):\n",
      "    # TODO: Implement me\n",
 
</s> remove     "def post_order_traversal(node, visit_func):\n",
    "    # TODO: Implement me\n",
    "    pass"
 </s> add     "    def pre_order_traversal(self, node, visit_func):\n",
    "        # TODO: Implement me\n",
    "        pass\n",
    "\n",
    "    def post_order_traversal(self,node, visit_func):\n",
    "        # TODO: Implement me\n",
    "        pass" </s> remove     "def in_order_traversal(node, visit_func):\n",
    "    # TODO: Implement me\n",
    "    pass\n",
 </s> add     "class BstDfs(Bst):\n", </s> remove     "def in_order_traversal(node, visit_func):\n",
    "    if node is not None:\n",
    "        in_order_traversal(node.left, visit_func)\n",
    "        visit_func(node)\n",
    "        in_order_traversal(node.right, visit_func)\n",
    "\n",
    "def pre_order_traversal(node, visit_func):\n",
    "    if node is not None:\n",
    "        visit_func(node)\n",
    "        pre_order_traversal(node.left, visit_func)\n",
    "        pre_order_traversal(node.right, visit_func)\n",
    "\n",
    "def post_order_traversal(node, visit_func):\n",
    "    if node is not None:\n",
    "        post_order_traversal(node.left, visit_func)\n",
    "        post_order_traversal(node.right, visit_func)\n",
    "        visit_func(node)"
 </s> add     "class BstDfs(Bst):\n",
    "\n",
    "    def in_order_traversal(self, node, visit_func):\n",
    "        if node is not None:\n",
    "            self.in_order_traversal(node.left, visit_func)\n",
    "            visit_func(node)\n",
    "            self.in_order_traversal(node.right, visit_func)\n",
    "\n",
    "    def pre_order_traversal(self, node, visit_func):\n",
    "        if node is not None:\n",
    "            visit_func(node)\n",
    "            self.pre_order_traversal(node.left, visit_func)\n",
    "            self.pre_order_traversal(node.right, visit_func)\n",
    "\n",
    "    def post_order_traversal(self, node, visit_func):\n",
    "        if node is not None:\n",
    "            self.post_order_traversal(node.left, visit_func)\n",
    "            self.post_order_traversal(node.right, visit_func)\n",
    "            visit_func(node)" </s> remove     "        pre_order_traversal(node, self.results.add_result)\n",
 </s> add     "        bst.pre_order_traversal(bst.root, self.results.add_result)\n", </s> remove     "        pre_order_traversal(node, self.results.add_result)\n",
 </s> add     "        bst.pre_order_traversal(bst.root, self.results.add_result)\n",
    "    def in_order_traversal(self, node, visit_func):\n",
      "def in_order_traversal(node, visit_func):\n",
      "    # TODO: Implement me\n",
      "    pass\n",
      "\n",
    "    def in_order_traversal(self, node, visit_func):\n",
      "    # TODO: Implement me\n",
      "    pass\n",
      "\n",
      "def post_order_traversal(node, visit_func):\n",
      "    # TODO: Implement me\n",
keep keep keep keep replace keep keep keep keep keep
 Move tree dfs to a class 
graphs_trees/tree_dfs/dfs_challenge.ipynb