code: def testIsThreadMainInThread(self):
      try:
          provided = MPI.Query_thread()
      except NotImplementedError:
          self.skipTest("mpi-query_thread")
      self.testIsThreadMain()
      T = [
          threading.Thread(target=self.testIsThreadMain)
          for _ in range(5)
      ]
      if provided == MPI.THREAD_MULTIPLE:
          for t in T:
              t.start()
          for t in T:
              t.join()
      elif provided == MPI.THREAD_SERIALIZED:
          for t in T:
              t.start()
              t.join()
      else:
          self.skipTest("mpi-thread_level")
  
file_path: mpi4py/test/test_threads.py
imports: import sys
  import mpi4py.rc
  from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 3 for calling the TestMPIThreads obj's underlying member method code with example usage: obj.testIsThreadMainInThread() without return types