      "def compress_string_alt(string):\n",
      "    if string is None or len(string) == 0:\n",
      "        return string\n",
      "    size = 0\n",
      "    count = 0\n",
      "    last_char_code = string[0]\n",
      "    for char_code in string:\n",
      "        if char_code == last_char_code:\n",
      "            count += 1\n",
      "        else:\n",
 
</s> remove     "    count = 0\n",
 </s> add  </s> remove     "        if char_code == last_char_code:\n",
    "            count += 1\n",
    "        else:\n",
 </s> add     "        if char_code != last_char_code:\n",
      "def compress_string_alt(string):\n",
      "    if string is None or len(string) == 0:\n",
      "        return string\n",
      "    size = 0\n",

      "    last_char_code = string[0]\n",
      "    for char_code in string:\n",
      "        if char_code == last_char_code:\n",
      "            count += 1\n",
      "        else:\n",
keep keep keep keep replace keep keep keep keep keep
 Reworked notebook: Added more detail to clarifying questions and test cases.  Reworked algorithm discussion, code, and unit test. 
arrays-strings/compress.ipynb