      "    compressed_string[pos] = last_char_code\n",
      "    compressed_string[pos + 1] = ord(str(count))\n",
      "    return compressed_string\n",
      "\n",
      "string0 = None\n",
      "string1 = bytearray('')\n",
      "string2 = bytearray('ABC')\n",
      "string3 = bytearray('AAABCCDDDD')\n",
      "print(compress_string(string0))\n",
      "print(compress_string(string1))\n",
      "print(compress_string(string2))\n",
      "print(compress_string(string3))"
     ]
    }
   ],
   "metadata": {
    "kernelspec": {
 
</s> remove     "string0 = None\n",
    "string1 = ''\n",
    "string2 = 'ABC'\n",
    "string3 = 'AAABCCDDDD'\n",
    "print(compress_string(string0))\n",
    "print(compress_string(string1))\n",
    "print(compress_string(string2))\n",
    "print(compress_string(string3))"
 </s> add     "run_tests(compress_string)" </s> remove     "def compress_string(string):\n",
 </s> add     "def compress_string_alt(string):\n",
    "run_tests(compress_string_alt)"
      "    compressed_string[pos] = last_char_code\n",
      "    compressed_string[pos + 1] = ord(str(count))\n",
      "    return compressed_string\n",
      "\n",
    "run_tests(compress_string_alt)"
    "run_tests(compress_string_alt)"
    "run_tests(compress_string_alt)"
    "run_tests(compress_string_alt)"
    "run_tests(compress_string_alt)"
    "run_tests(compress_string_alt)"
    "run_tests(compress_string_alt)"
    "run_tests(compress_string_alt)"
     ]
    }
   ],
   "metadata": {
    "kernelspec": {
keep keep keep keep replace replace replace replace replace replace replace replace keep keep keep keep keep
 Updated unit test to use nose and moved it to Test Case section. 
arrays-strings/compress.ipynb