code: def _py2_crc16(value):
      
      crc = 0
      for byte in value:
          crc = ((crc << 8) & 0xffff) ^ \
                _CRC16_LOOKUP[((crc >> 8) ^ ord(byte)) & 0xff]
      return crc
docs: Calculate the CRC for the value in Python 2
  
      :param str value: The value to return for the CRC Checksum
      :rtype: int