def running_jobs(self, exit_on_error=True):
        """Initialize multiprocessing."""
        with self.handling_exceptions():
            if self.using_jobs:
                from concurrent.futures import ProcessPoolExecutor
                try:
                    with ProcessPoolExecutor(self.jobs) as self.executor:
                        yield
                finally:
                    self.executor = None
            else:
                yield
        if exit_on_error:
            self.exit_on_error()
Initialize multiprocessing.