      "* Space: O(1)\n",
      "\n",
      "### Append\n",
      "\n",
      "* If the data we are inserting is NULL, return\n",
      "* Create a node with the input data\n",
      "* If this is an empty list\n",
      "    * Assign the head to the node\n",
      "* Else\n",
      "    * Iterate to the end of the list\n",
 
</s> remove     "* If the data we are inserting is NULL, return\n",
 </s> add     "* If the data we are inserting is None, return\n", </s> remove     "* If data we are finding is NULL, return\n",
 </s> add     "* If data we are finding is None, return\n", </s> remove     "* If data we are deleting is NULL, return\n",
 </s> add     "* If data we are deleting is None, return\n", </s> remove     "    * if first and second lists are NULL AND carry is zero\n",
    "        * Return NULL\n",
 </s> add     "    * if first and second lists are None AND carry is zero\n",
    "        * Return None\n", </s> remove     "    * Only add if a node is not NULL\n",
 </s> add     "    * Only add if a node is not None\n",
    "* If the data we are inserting is None, return\n",
      "* Space: O(1)\n",
      "\n",
      "### Append\n",
      "\n",
    "* If the data we are inserting is None, return\n",
      "* Create a node with the input data\n",
      "* If this is an empty list\n",
      "    * Assign the head to the node\n",
      "* Else\n",
      "    * Iterate to the end of the list\n",
keep keep keep keep replace keep keep keep keep keep
 Changed discussions of NULL to None to be more Pythonic. 
linked_lists/linked_list/linked_list_solution.ipynb