def _initialize_executor(self) -> None:
        """Initialize a new ProcessPoolExecutor and reset task counter."""
        if self.executor is not None:
            self.executor.shutdown(wait=False)
            self.executor = None
            gc.collect() 
        self.executor = ProcessPoolExecutor(max_workers=self.max_workers)
        self.task_counter = 0
Initialize a new ProcessPoolExecutor and reset task counter.
verl/utils/reward_score/simplelr_math.py