      "\n",
      "### Insert to Front\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",
      "    * Set the node.next to the head\n",
      "    * Set the head to the node\n",
      "\n",
      "Complexity:\n",
      "* Time: O(1)\n",
      "* Space: O(1)\n",
      "\n",
 
</s> remove     "    * Just the head"
 </s> add     "    * Just the head\n",
    "* Can we insert None values?\n",
    "    * No" </s> remove     "    * Just the head"
 </s> add     "    * Just the head\n",
    "* Can we insert None values?\n",
    "    * No" </s> remove     "            return\n",
    "        node = Node(data)\n",
    "        if self.head is None:\n",
    "            self.head = node\n",
    "        else:\n",
    "            node.next = self.head\n",
    "            self.head = node\n",
 </s> add     "            return None\n",
    "        node = Node(data, self.head)\n",
    "        self.head = node\n", </s> remove     "    def append(self, data, next_node=None):\n",
 </s> add     "    def append(self, data):\n",
    "* Create a node with the input data, set node.next to head\n",
    "* Assign the head to the node\n",
      "\n",
      "### Insert to Front\n",
      "\n",
      "* If the data we are inserting is None, return\n",
    "* Create a node with the input data, set node.next to head\n",
    "* Assign the head to the node\n",
    "* Create a node with the input data, set node.next to head\n",
    "* Assign the head to the node\n",
    "* Create a node with the input data, set node.next to head\n",
    "* Assign the head to the node\n",
    "* Create a node with the input data, set node.next to head\n",
    "* Assign the head to the node\n",
    "* Create a node with the input data, set node.next to head\n",
    "* Assign the head to the node\n",
    "* Create a node with the input data, set node.next to head\n",
    "* Assign the head to the node\n",
      "\n",
      "Complexity:\n",
      "* Time: O(1)\n",
      "* Space: O(1)\n",
      "\n",
keep keep keep keep replace replace replace replace replace replace keep keep keep keep keep
 Polish linked list challenge and solution

Update algorithm discussion, solution, and constraints. 
linked_lists/linked_list/linked_list_solution.ipynb