      "class TestGraph(object):\n",
      "\n",
      "    def create_graph(self):\n",
      "        graph = Graph()\n",
      "        for id in range(0, 6):\n",
      "            graph.add_node(id)\n",
      "        return graph\n",
      "\n",
      "    def test_graph(self):\n",
      "        graph = self.create_graph()\n",
      "\n",
 
</s>
    "        for key in range(0, 6):\n",
    "            graph.add_node(key)\n",
      "class TestGraph(object):\n",
      "\n",
      "    def create_graph(self):\n",
      "        graph = Graph()\n",
    "        for key in range(0, 6):\n",
    "            graph.add_node(key)\n",
    "        for key in range(0, 6):\n",
    "            graph.add_node(key)\n",
      "        return graph\n",
      "\n",
      "    def test_graph(self):\n",
      "        graph = self.create_graph()\n",
      "\n",
keep keep keep keep replace replace keep keep keep keep keep
 Rework graph challenge and solution (#90)
graphs_trees/graph/graph_solution.ipynb