def __create(self, opcode):
        tftpassert(self.classes.has_key(opcode),
                   "Unsupported opcode: %d" % opcode)

        packet = self.classes[opcode]()

        return packet
This method returns the appropriate class object corresponding to
dataset/ETHPy150Open msoulier/tftpy/tftpy/TftpPacketFactory.py/TftpPacketFactory.__create