code: def join_threads(threads):
      count = 0
      num = len(threads)
      while count < num:
          with cv:
              while not done_threads:
                  cv.wait()
              idx = done_threads[-1]
              done_threads.pop()
          threads[idx].join()
          print("BytePS launcher: joined local rank ", idx)
          count += 1
  
file_path: byteps/launcher/launch.py
imports: from __future__ import print_function
  import os
  import re
  import subprocess
  import threading
  import sys
  import time
  from functools import reduce
label_desc: Use image node_id 6 for calling a global function with example usage: join_threads(threads) without return types