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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 _send_rtcp_pli(self, media_ssrc):
 """ Send an RTCP packet to report picture loss. """

        if self.__rtcp_ssrc is not None:
            packet = RtcpPsfbPacket(fmt=RTCP_PSFB_PLI, ssrc=self.__rtcp_ssrc, media_ssrc=media_ssrc)
            await self._send_rtcp(packet)