Clarify return value of executor.shutdown

parsl/executors/base.py

@@ -74,7 +74,7 @@ def submit(self, func: Callable, resource_specification: Dict[str, Any], *args:
         pass
 
     @abstractmethod
-    def shutdown(self) -> bool:
+    def shutdown(self) -> None:
         """Shutdown the executor.
 
         This includes all attached resources such as workers and controllers.

parsl/executors/taskvine/executor.py

@@ -614,7 +614,6 @@ def shutdown(self, *args, **kwargs):
             self._factory_process.join()
 
         logger.debug("TaskVine shutdown completed")
-        return True
 
     @wrap_with_logs
     def _collect_taskvine_results(self):

parsl/executors/threads.py

@@ -72,9 +72,8 @@ def shutdown(self, block=True):
 
         """
         logger.debug("Shutting down executor, which involves waiting for running tasks to complete")
-        x = self.executor.shutdown(wait=block)
+        self.executor.shutdown(wait=block)
         logger.debug("Done with executor shutdown")
-        return x
 
     def monitor_resources(self):
         """Resource monitoring sometimes deadlocks when using threads, so this function

parsl/executors/workqueue/executor.py

@@ -707,7 +707,6 @@ def shutdown(self, *args, **kwargs):
         self.collector_thread.join()
 
         logger.debug("Work Queue shutdown completed")
-        return True
 
     @wrap_with_logs
     def _collect_work_queue_results(self):