def terminate(self):
        """
        Send termination signal to DAG parsing processor manager
        and expect it to terminate all DAG file processors.
        """
        self.log.info("Sending termination message to manager.")
        self._child_signal_conn.send(DagParsingSignal.TERMINATE_MANAGER)
Send termination signal to DAG parsing processor manager
        and expect it to terminate all DAG file processors.