<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _py2_crc16(value):
 """Calculate the CRC for the value in Python 2 :param str value: The value to return for the CRC Checksum :rtype: int """

    crc = 0
    for byte in value:
        crc = ((crc << 8) & 0xffff) ^ \
              _CRC16_LOOKUP[((crc >> 8) ^ ord(byte)) & 0xff]
    return crc