code: def periodic(period=60.0, file=sys.stderr):
      
      import threading
      import time
      S = _StatsThread(period=period, file=file)
      T = threading.Thread(target=S)
      T.daemon = True
      T.start()
docs: Start a daemon thread which will periodically print GC stats
  
      :param period: Update period in seconds
      :param file: A writable file-like object