      "\n",
      "\n",
      "class Node:\n",
      "\n",
      "    def __init__(self, id):\n",
      "        self.id = id\n",
      "        self.visit_state = State.unvisited\n",
      "        self.adjacent = {}  # key = node, val = weight\n",
      "\n",
      "    def __str__(self):\n",
      "        return str(self.id)\n",
 
</s> remove     "        self.adjacent = {}  # key = node, val = weight\n",
 </s> add     "        self.incoming_edges = 0\n",
    "        self.adj_nodes = {}  # Key = key, val = Node\n",
    "        self.adj_weights = {}  # Key = key, val = weight\n",
    "\n",
    "    def __repr__(self):\n",
    "        return str(self.key)\n", </s> remove     "    def __init__(self, id):\n",
    "        # TODO: Implement me\n",
    "        self.adjacent = {}  # key = node, val = weight\n",
 </s> add     "    def __init__(self, key):\n",
    "        self.key = key\n",
    "        self.visit_state = State.unvisited\n",
    "        self.incoming_edges = 0\n",
    "        self.adj_nodes = {}  # Key = key, val = Node\n",
    "        self.adj_weights = {}  # Key = Node, val = weight\n", </s> remove     "    def __str__(self):\n",
    "        return str(self.id)\n",
 </s> add     "    def __lt__(self, other):\n",
    "        return self.key < other.key\n", </s> remove     "    def __str__(self):\n",
 </s> add     "    def __repr__(self):\n", </s> remove     "        # TODO: Implement me\n",
    "        self.nodes = {}  # key = node id, val = node\n",
 </s> add     "        self.nodes = {}  # Key = key, val = Node\n",
    "    def __init__(self, key):\n",
    "        self.key = key\n",
      "\n",
      "\n",
      "class Node:\n",
      "\n",
    "    def __init__(self, key):\n",
    "        self.key = key\n",
    "    def __init__(self, key):\n",
    "        self.key = key\n",
      "        self.visit_state = State.unvisited\n",
      "        self.adjacent = {}  # key = node, val = weight\n",
      "\n",
      "    def __str__(self):\n",
      "        return str(self.id)\n",
keep keep keep keep replace replace keep keep keep keep keep
 Rework graph challenge and solution (#90) 
graphs_trees/graph/graph_solution.ipynb