code: def test_rejoin_idempotent():
      with ThreadPoolExecutor(2) as e:
  
          def f():
              secede()
              for _ in range(5):
                  rejoin()
              return 1
  
          future = e.submit(f)
          result = future.result()
  
file_path: distributed/distributed/tests/test_threadpoolexecutor.py
imports: from __future__ import annotations
  import threading
  from time import sleep
  from distributed.metrics import time
  from distributed.threadpoolexecutor import ThreadPoolExecutor, rejoin, secede
label_desc: Use image node_id 7 for calling a global function with example usage: test_rejoin_idempotent() and returns: int