     "metadata": {},
     "source": [
      "## Test Cases\n",
      "\n",
      "* None -> None\n",
      "* Empty input -> []\n",
      "* One element -> [element]\n",
      "* Two or more elements"
     ]
    },
 
</s> remove     "* Is a naiive solution sufficient (ie not in-place)?\n",
 </s> add     "* Is a naive solution sufficient (ie not in-place)?\n", </s> remove     "def quick_sort(data):\n",
    "    # TODO: Implement me\n",
    "    pass"
 </s> add     "class QuickSort(object):\n",
    "\n",
    "    def sort(self, data):\n",
    "        # TODO: Implement me\n",
    "        pass" </s> remove     "from nose.tools import assert_equal\n",
 </s> add     "from nose.tools import assert_equal, assert_raises\n", </s> remove     "        data = None\n",
    "        sorted_data = func(data)\n",
    "        assert_equal(sorted_data, None)\n",
 </s> add     "        assert_raises(TypeError, quick_sort.sort, None)\n",
    "* None -> Exception\n",
     "metadata": {},
     "source": [
      "## Test Cases\n",
      "\n",
    "* None -> Exception\n",
      "* Empty input -> []\n",
      "* One element -> [element]\n",
      "* Two or more elements"
     ]
    },
keep keep keep keep replace keep keep keep keep keep
 Update quicksort challenge (#134)

Update constraints, test cases, code, algorithm, and tests. 
sorting_searching/quick_sort/quick_sort_challenge.ipynb