1  import os
       2  import sys
       3  import threading
       4  import traceback
       5  
       6  
       7  NLOOPS = 50
       8  NTHREADS = 30
       9  
      10  
      11  def t1():
      12      try:
      13          from concurrent.futures import ThreadPoolExecutor
      14      except Exception:
      15          traceback.print_exc()
      16          os._exit(1)
      17  
      18  def t2():
      19      try:
      20          from concurrent.futures.thread import ThreadPoolExecutor
      21      except Exception:
      22          traceback.print_exc()
      23          os._exit(1)
      24  
      25  def main():
      26      for j in range(NLOOPS):
      27          threads = []
      28          for i in range(NTHREADS):
      29              threads.append(threading.Thread(target=t2 if i % 1 else t1))
      30          for thread in threads:
      31              thread.start()
      32          for thread in threads:
      33              thread.join()
      34          sys.modules.pop('concurrent.futures', None)
      35          sys.modules.pop('concurrent.futures.thread', None)
      36  
      37  if __name__ == "__main__":
      38      main()