      "from nose.tools import assert_equal\n",
      "from nose.tools import raises\n",
      "\n",
      "\n",
      "class TestBstSuccessor(object):\n",
      "\n",
      "    @raises(Exception)\n",
      "    def test_bst_successor_empty(self):\n",
      "        bst_successor = BstSuccessor()\n",
      "        bst_successor.get_next(None)\n",
 
</s> remove     "class TestBstSuccessor(object):\n",
 </s> add     "class TestBstSuccessor(unittest.TestCase):\n", </s> remove     "    @raises(Exception)\n",
 </s> add  </s> remove     "    @raises(Exception)\n",
 </s> add  </s> remove     "from nose.tools import assert_equal\n",
    "from nose.tools import raises\n",
 </s> add     "import unittest\n", </s> remove     "from nose.tools import assert_equal\n",
    "from nose.tools import raises\n",
 </s> add     "import unittest\n",
    "class TestBstSuccessor(unittest.TestCase):\n",
      "from nose.tools import assert_equal\n",
      "from nose.tools import raises\n",
      "\n",
      "\n",
    "class TestBstSuccessor(unittest.TestCase):\n",
      "\n",
      "    @raises(Exception)\n",
      "    def test_bst_successor_empty(self):\n",
      "        bst_successor = BstSuccessor()\n",
      "        bst_successor.get_next(None)\n",
keep keep keep keep replace keep keep keep keep keep
 #273: Remove nose dependency for graphs_trees/ (#277) 
graphs_trees/bst_successor/bst_successor_challenge.ipynb