      "        graph.add_edge(4, 0, weight=7)\n",
      "        graph.add_edge(5, 4, weight=8)\n",
      "        graph.add_edge(5, 2, weight=9)\n",
      "\n",
      "        assert_equal(graph.nodes[0].adjacent[graph.nodes[1]], 5)\n",
      "        assert_equal(graph.nodes[0].adjacent[graph.nodes[5]], 2)\n",
      "        assert_equal(graph.nodes[1].adjacent[graph.nodes[2]], 3)\n",
      "        assert_equal(graph.nodes[2].adjacent[graph.nodes[3]], 4)\n",
      "        assert_equal(graph.nodes[3].adjacent[graph.nodes[4]], 5)\n",
      "        assert_equal(graph.nodes[3].adjacent[graph.nodes[5]], 6)\n",
      "        assert_equal(graph.nodes[4].adjacent[graph.nodes[0]], 7)\n",
      "        assert_equal(graph.nodes[5].adjacent[graph.nodes[4]], 8)\n",
      "        assert_equal(graph.nodes[5].adjacent[graph.nodes[2]], 9)\n",
      "\n",
      "        print('Success: test_graph')\n",
      "\n",
      "    def test_graph_undirected(self):\n",
      "        graph = self.create_graph()\n",
 
</s> remove     "        assert_equal(graph.nodes[0].adjacent[graph.nodes[1]], 5)\n",
    "        assert_equal(graph.nodes[0].adjacent[graph.nodes[5]], 2)\n",
    "        assert_equal(graph.nodes[1].adjacent[graph.nodes[2]], 3)\n",
    "        assert_equal(graph.nodes[2].adjacent[graph.nodes[3]], 4)\n",
    "        assert_equal(graph.nodes[3].adjacent[graph.nodes[4]], 5)\n",
    "        assert_equal(graph.nodes[3].adjacent[graph.nodes[5]], 6)\n",
    "        assert_equal(graph.nodes[4].adjacent[graph.nodes[0]], 7)\n",
    "        assert_equal(graph.nodes[5].adjacent[graph.nodes[4]], 8)\n",
    "        assert_equal(graph.nodes[5].adjacent[graph.nodes[2]], 9)\n",
 </s> add     "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n", </s> remove     "        assert_equal(graph.nodes[0].adjacent[graph.nodes[1]], 5)\n",
    "        assert_equal(graph.nodes[1].adjacent[graph.nodes[0]], 5)\n",
    "        assert_equal(graph.nodes[0].adjacent[graph.nodes[5]], 2)\n",
    "        assert_equal(graph.nodes[5].adjacent[graph.nodes[0]], 2)\n",
    "        assert_equal(graph.nodes[1].adjacent[graph.nodes[2]], 3)\n",
    "        assert_equal(graph.nodes[2].adjacent[graph.nodes[1]], 3)\n",
 </s> add     "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[0].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[0].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[1].key], 3)\n", </s> remove     "        assert_equal(graph.nodes[0].adjacent[graph.nodes[1]], 5)\n",
    "        assert_equal(graph.nodes[1].adjacent[graph.nodes[0]], 5)\n",
    "        assert_equal(graph.nodes[0].adjacent[graph.nodes[5]], 2)\n",
    "        assert_equal(graph.nodes[5].adjacent[graph.nodes[0]], 2)\n",
    "        assert_equal(graph.nodes[1].adjacent[graph.nodes[2]], 3)\n",
    "        assert_equal(graph.nodes[2].adjacent[graph.nodes[1]], 3)\n",
 </s> add     "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[0].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[0].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[1].key], 3)\n", </s> remove     "\n",
 </s> add  </s> remove     "\n",
 </s> add 
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
      "        graph.add_edge(4, 0, weight=7)\n",
      "        graph.add_edge(5, 4, weight=8)\n",
      "        graph.add_edge(5, 2, weight=9)\n",
      "\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[1].key], 5)\n",
    "        assert_equal(graph.nodes[0].adj_weights[graph.nodes[5].key], 2)\n",
    "        assert_equal(graph.nodes[1].adj_weights[graph.nodes[2].key], 3)\n",
    "        assert_equal(graph.nodes[2].adj_weights[graph.nodes[3].key], 4)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[4].key], 5)\n",
    "        assert_equal(graph.nodes[3].adj_weights[graph.nodes[5].key], 6)\n",
    "        assert_equal(graph.nodes[4].adj_weights[graph.nodes[0].key], 7)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[4].key], 8)\n",
    "        assert_equal(graph.nodes[5].adj_weights[graph.nodes[2].key], 9)\n",
    "\n",
    "        assert_equal(graph.nodes[0].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[2].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[3].incoming_edges, 1)\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 2)\n",
    "        assert_equal(graph.nodes[5].incoming_edges, 2)\n",
    "\n",
    "        graph.nodes[0].remove_neighbor(graph.nodes[1])\n",
    "        assert_equal(graph.nodes[1].incoming_edges, 0)\n",
    "        graph.nodes[3].remove_neighbor(graph.nodes[4])\n",
    "        assert_equal(graph.nodes[4].incoming_edges, 1)\n",
    "\n",
    "        assert_equal(graph.nodes[0] < graph.nodes[1], True)\n",
      "\n",
      "        print('Success: test_graph')\n",
      "\n",
      "    def test_graph_undirected(self):\n",
      "        graph = self.create_graph()\n",
keep keep keep keep replace replace replace replace replace replace replace replace replace keep keep keep keep keep
 Rework graph challenge and solution (#90) 
graphs_trees/graph/graph_challenge.ipynb