code: def test_nested_submit(backend):
      with backend(5) as executor:
          futures = [
              executor.submit(nested, executor) for i in range(5)
          ]
  
          results = executor.async_get(futures, timeout=2)
  
          for r in results:
              assert r.value == 35
  
imports: import os
  import time
  import pytest
  from orion.executor.base import AsyncException, ExecutorClosed, executor_factory
  from orion.executor.dask_backend import HAS_DASK, Dask
  from orion.executor.multiprocess_backend import PoolExecutor
  from orion.executor.ray_backend import HAS_RAY, Ray
  from orion.executor.single_backend import SingleExecutor
label_desc: Use image node_id 24 for calling a global function with example usage: test_nested_submit(backend) without return types