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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:
 async def _retransmit(self, sequence_number):
 """ Retransmit an RTP packet which was reported as lost. """

        packet = self.__rtp_history.get(sequence_number % RTP_HISTORY_SIZE)
        if packet and packet.sequence_number == sequence_number:
            if self.__rtx_payload_type is not None:
                packet = wrap_rtx(packet,
                                  payload_type=self.__rtx_payload_type,
                                  sequence_number=self.__rtx_sequence_number,
                                  ssrc=self._rtx_ssrc)
                self.__rtx_sequence_number = uint16_add(self.__rtx_sequence_number, 1)

            self.__log_debug('> %s', packet)
            packet_bytes = packet.serialize(self.__rtp_header_extensions_map)
            await self.transport._send_rtp(packet_bytes)