code: def start_regularly_cleanup(self, regularly_cleanup_interval=None, only_read=False):
          
          if not hasattr(self, 'cleanup_supervisor') or self.cleanup_supervisor is None:
              if regularly_cleanup_interval is None or not isinstance(regularly_cleanup_interval, int):
                  regularly_cleanup_interval = self.regularly_cleanup_interval
  
              cleanup_supervisor = CleanupSupervisorThread(cache=self, logger=self.logger,
                                                           interval=regularly_cleanup_interval)
              cleanup_supervisor.start()
              self.cleanup_supervisor = cleanup_supervisor
              return True
          else:
              self.logger.warning('Already have a regularly cleanup thread - %s' % self.cleanup_supervisor.name)
              return False
docs: >>> cache = Cache(regularly_cleanup=False, log_level=logging.ERROR)
          >>> cache.start_regularly_cleanup()
          True
          >>> cache.start_regularly_cleanup()
          False