agent_signal = self._direct_scheduler_conn.recv()
                self.log.debug("Received %s signal from DagFileProcessorAgent", agent_signal)
                if agent_signal == DagParsingSignal.TERMINATE_MANAGER:
                    self.terminate()
                    break
                elif agent_signal == DagParsingSignal.END_MANAGER:
                    self.end()
                    sys.exit(os.EX_OK)
                elif agent_signal == DagParsingSignal.AGENT_RUN_ONCE:
                    
                    pass
                elif isinstance(agent_signal, CallbackRequest):
                    self._add_callback_to_queue(agent_signal)
                else:
                    raise ValueError(f"Invalid message {type(agent_signal)}")
            if not ready and not self._async_mode:
                
                
                
                
                
                self.log.warning(
                    "wait() unexpectedly returned nothing ready after infinite timeout (%r)!", poll_time
                )
                continue
            for sentinel in ready:
                if sentinel is self._direct_scheduler_conn:
                    continue
                processor = self.waitables.get(sentinel)
                if not processor: