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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 decode(self, bytes):
 """ Decodes the packet off the byte string. """


        self.buffer = bytes
        self._pos = 0

        Packet = identifier.get_packet_from_id(self._read_variunt())

        # unknown packets will be None from the identifier
        if Packet is None:
            return None

        packet = Packet()
        packet.ParseFromString(self.remaining_bytes())
        return packet