      "        assert_equal(data, [])\n",
      "\n",
      "        print('One element')\n",
      "        data = [5]\n",
      "        merge_sort(data)\n",
      "        assert_equal(data, [5])\n",
      "\n",
      "        print('Two or more elements')\n",
      "        data = [5, 1, 7, 2, 6, -3, 5, 7, -1]\n",
      "        data = merge_sort(data)\n",
      "        assert_equal(data, sorted(data))\n",
 
</s> remove     "        merge_sort(data)\n",
    "        assert_equal(data, [5])\n",
 </s> add     "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, [5])\n", </s> remove     "        data = merge_sort(data)\n",
    "        assert_equal(data, sorted(data))\n",
 </s> add     "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, sorted(data))\n", </s> remove     "        data = merge_sort(data)\n",
    "        assert_equal(data, sorted(data))\n",
 </s> add     "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, sorted(data))\n", </s> remove     "        merge_sort(data)\n",
    "        assert_equal(data, [])\n",
 </s> add     "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, [])\n", </s> remove     "        merge_sort(data)\n",
    "        assert_equal(data, [])\n",
 </s> add     "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, [])\n",
    "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, [5])\n",
      "        assert_equal(data, [])\n",
      "\n",
      "        print('One element')\n",
      "        data = [5]\n",
    "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, [5])\n",
    "        sorted_data = merge_sort(data)\n",
    "        assert_equal(sorted_data, [5])\n",
      "\n",
      "        print('Two or more elements')\n",
      "        data = [5, 1, 7, 2, 6, -3, 5, 7, -1]\n",
      "        data = merge_sort(data)\n",
      "        assert_equal(data, sorted(data))\n",
keep keep keep keep replace replace keep keep keep keep keep
 the 'Two or more elements' test doesn't actually test if the list was sorted properly 
sorting_searching/merge_sort/merge_sort_challenge.ipynb