code: def packet_handle(self):
          
          cmd = self.in_packet.command & 0xF0
          
          if cmd == NC.CMD_CONNACK:
              return self.handle_connack()
          elif cmd == NC.CMD_PINGRESP:
              return self.handle_pingresp()
          elif cmd == NC.CMD_PUBLISH:
              return self.handle_publish()
          elif cmd == NC.CMD_PUBACK:
              return self.handle_puback()
          elif cmd == NC.CMD_PUBREC:
              return self.handle_pubrec()
          elif cmd == NC.CMD_PUBREL:
              return self.handle_pubrel()
          elif cmd == NC.CMD_PUBCOMP:
              return self.handle_pubcomp()
          elif cmd == NC.CMD_SUBSCRIBE:
              sys.exit(-1)
          elif cmd == NC.CMD_SUBACK:
              return self.handle_suback()
          elif cmd == NC.CMD_UNSUBSCRIBE:
              print "Received UNSUBSCRIBE"
              sys.exit(-1)
          elif cmd == NC.CMD_UNSUBACK:
              return self.handle_unsuback()
          else:
              self.logger.warning("Unknown protocol. Cmd = %d", cmd)
              return NC.ERR_PROTOCOL
docs: Incoming packet handler dispatcher.