code: def test_cancel_future_after_shutdown_no_wait(backend):
      bpe = BatchPoolExecutor(
          backend=backend, project="hail-vdc", image=PYTHON_DILL_IMAGE
      )
  
      def sleep_forever():
          while True:
              time.sleep(3600)
  
      future = bpe.submit(sleep_forever)
      bpe.shutdown(wait=False)
      was_cancelled = future.cancel()
      assert was_cancelled
      assert future.cancelled()
  
imports: import asyncio
  import time
  import pytest
  from hailtop.batch import BatchPoolExecutor, ServiceBackend
  from hailtop.config import get_user_config
  from hailtop.utils import sync_sleep_before_try
  from hailtop.batch_client.client import BatchClient
label_desc: Use image node_id 7 for calling a global function with example usage: test_cancel_future_after_shutdown_no_wait(backend) without return types