Fix #13, PEP8-ify notebooks.

stacks_queues/queue_list/queue_list_solution.ipynb

@@ -34,7 +34,6 @@
    "source": [
     "## Constraints\n",
     "\n",
-
     "* If there is one item in the list, do you expect the first and last pointers to both point to it?\n",
     "    * Yes\n",
     "* If there are no items on the list, do you expect the first and last pointers to be None?\n",
@@ -118,13 +117,14 @@
    "source": [
     "%%writefile queue_list.py\n",
     "class Node(object):\n",
-    "    \n",
+    "\n",
     "    def __init__(self, data):\n",
     "        self.data = data\n",
     "        self.next = None\n",
     "\n",
+    "\n",
     "class Queue(object):\n",
-    "    \n",
+    "\n",
     "    def __init__(self):\n",
     "        self.first = None\n",
     "        self.last = None\n",
@@ -142,7 +142,7 @@
     "        # Empty list\n",
     "        if self.first is None and self.last is None:\n",
     "            return None\n",
-    "        \n",
+    "\n",
     "        # Remove only element from a one element list\n",
     "        elif self.first == self.last:\n",
     "            data = self.first.data\n",
@@ -195,7 +195,7 @@
     "\n",
     "\n",
     "class TestQueue(object):\n",
-    "    \n",
+    "\n",
     "    # TODO: It would be better if we had unit tests for each\n",
     "    # method in addition to the following end-to-end test\n",
     "    def test_end_to_end(self):\n",
@@ -218,13 +218,15 @@
     "        assert_equal(queue.dequeue(), 2)\n",
     "        assert_equal(queue.dequeue(), 3)\n",
     "        assert_equal(queue.dequeue(), 4)\n",
-    "        \n",
+    "\n",
     "        print('Success: test_end_to_end')\n",
     "\n",
+    "\n",
     "def main():\n",
     "    test = TestQueue()\n",
     "    test.test_end_to_end()\n",
-    "    \n",
+    "\n",
+    "\n",
     "if __name__ == '__main__':\n",
     "    main()"
    ]