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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 parse(self, buffer):
 """This method is used to parse an existing datagram into its corresponding TftpPacket object. The buffer is the raw bytes off of the network."""

        log.debug("parsing a %d byte packet" % len(buffer))
        (opcode,) = struct.unpack(str("!H"), buffer[:2])
        log.debug("opcode is %d" % opcode)
        packet = self.__create(opcode)
        packet.buffer = buffer
        return packet.decode()