<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def mustRetransmit(self):
 """ Check to see if this packet must be retransmitted until it was received. Packets which contain a connection-state changing flag (SYN or FIN) or a non-zero amount of data can be retransmitted. """

        if self.syn or self.fin or self.dlen:
            return True
        return False