      "\n",
      "    def add(self, first_list, second_list):\n",
      "        if first_list is None or second_list is None:\n",
      "            return None\n",
      "        head = self.__add__(first_list.head, second_list.head, 0)\n",
      "        return MyLinkedList(head)"
     ]
    },
    {
     "cell_type": "markdown",
 
</s> remove     "    def add(self, first_list, second_list):\n",
 </s> add     "    def add_reverse(self, first_list, second_list):\n", </s> remove     "        node.next = self.__add__(first_node.next if first_node is not None else None, \n",
    "                                 second_node.next if first_node is not None else None, \n",
    "                                 new_carry)\n",
 </s> add     "        node.next = self.__add_reverse__(first_node.next if first_node is not None else None, \n",
    "                                     second_node.next if first_node is not None else None, \n",
    "                                     new_carry)\n", </s> remove     "    def add(self, first_list, second_list):\n",
 </s> add     "    def add_reverse(self, first_list, second_list):\n", </s> remove     "    def __add__(self, first_node, second_node, carry):\n",
 </s> add     "    def __add_reverse__(self, first_node, second_node, carry):\n", </s> remove     "    test.test_add()\n",
 </s> add     "    test.test_add_reverse()\n",
    "        head = self.__add_reverse__(first_list.head, second_list.head, 0)\n",
      "\n",
      "    def add(self, first_list, second_list):\n",
      "        if first_list is None or second_list is None:\n",
      "            return None\n",
    "        head = self.__add_reverse__(first_list.head, second_list.head, 0)\n",
      "        return MyLinkedList(head)"
     ]
    },
    {
     "cell_type": "markdown",
keep keep keep keep replace keep keep keep keep keep
 Renamed unit test method to be more descriptive. 
linked_lists/add_reverse/add_reverse_solution.ipynb