      "%%writefile test_priority_queue.py\n",
      "from nose.tools import assert_equal\n",
      "\n",
      "\n",
      "class TestPriorityQueue(object):\n",
      "\n",
      "    def test_priority_queue(self):\n",
      "        priority_queue = PriorityQueue()\n",
      "        assert_equal(priority_queue.extract_min(), None)\n",
      "        priority_queue.insert(PriorityQueueNode('a', 20))\n",
 
</s> remove     "class TestPriorityQueue(object):\n",
 </s> add     "class TestPriorityQueue(unittest.TestCase):\n", </s> remove     "        assert_equal(priority_queue.extract_min(), None)\n",
 </s> add     "        self.assertEqual(priority_queue.extract_min(), None)\n", </s> remove     "        assert_equal(priority_queue.extract_min(), None)\n",
 </s> add     "        self.assertEqual(priority_queue.extract_min(), None)\n", </s> remove     "from nose.tools import assert_equal\n",
 </s> add     "import unittest\n", </s> remove     "from nose.tools import assert_equal\n",
 </s> add     "import unittest\n",
    "class TestPriorityQueue(unittest.TestCase):\n",
      "%%writefile test_priority_queue.py\n",
      "from nose.tools import assert_equal\n",
      "\n",
      "\n",
    "class TestPriorityQueue(unittest.TestCase):\n",
      "\n",
      "    def test_priority_queue(self):\n",
      "        priority_queue = PriorityQueue()\n",
      "        assert_equal(priority_queue.extract_min(), None)\n",
      "        priority_queue.insert(PriorityQueueNode('a', 20))\n",
keep keep keep keep replace keep keep keep keep keep
 #273: Remove nose dependency for arrays_strings/ (#274) 
arrays_strings/priority_queue/priority_queue_solution.ipynb