'Returns True if calculated checksum matches checksum attatched to packet, otherwise False'

def _check(self):

    newChecksum = _Checksum()
    for d in self.bytes[1:(-1)]:
        newChecksum.addData(d)
    testCRC = newChecksum.getResult()
    if (testCRC == self.CRC):
        return True
    else:
        return (False, testCRC, self.CRC)
