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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def transmit_tc_bpdu(self):
 """ Set send_tc_flg to send Topology Change BPDU. """

        if not self.send_tc_flg:
            timer = datetime.timedelta(seconds=self.port_times.max_age
                                       + self.port_times.forward_delay)
            self.send_tc_timer = datetime.datetime.today() + timer
            self.send_tc_flg = True