      "def list_of_chars(chars):\n",
      "    if chars is None:\n",
      "        return None\n",
      "    size = len(chars)\n",
      "    for i in range(size/2):\n",
      "        chars[i], chars[size-1-i] = \\\n",
      "            chars[size-1-i], chars[i]\n",
      "    return chars"
     ]
    },
 
</s> remove     "    pivot_index = int(len(data) / 2)\n",
 </s> add     "    pivot_index = len(data) // 2\n", </s> remove     "    mid = int(len(data) / 2)\n",
 </s> add     "    mid = len(data) // 2\n",
    "    for i in range(size//2):\n",
      "def list_of_chars(chars):\n",
      "    if chars is None:\n",
      "        return None\n",
      "    size = len(chars)\n",
    "    for i in range(size//2):\n",
      "        chars[i], chars[size-1-i] = \\\n",
      "            chars[size-1-i], chars[i]\n",
      "    return chars"
     ]
    },
keep keep keep keep replace keep keep keep keep keep
 Fixed Python2 vs Python3 division compatibility. 
arrays_strings/reverse_string/reverse_string_solution.ipynb