code: def run(self):
          
  
          idle_watchers = []
  
          while True:
              try:
                  if self._work_queue.empty() and len(idle_watchers) > 0:
                      for watcher in idle_watchers:
                          try:
                              watcher()
                          except: # pylint:disable=bare-except;We can't let one idle watcher failure impact any other watcher
                              self._logger.exception("Error inside queue idle watcher")
  
                      idle_watchers = []
  
                  item = self._work_queue.get()
  
                  # Handle special actions that are not RPCs
                  if item is STOP_WORKER_ITEM:
                      return
                  elif isinstance(item, MarkLocationItem):
                      item.callback()
                      continue
                  elif isinstance(item, WaitIdleItem):
                      idle_watchers.append(item.callback)
                      continue
                  elif not isinstance(item, WorkItem):
                      self._logger.error("Invalid item passed to WorkQueueThread: %s, ignoring", item)
                      continue
  
                  self.direct_dispatch(item.arg, item.callback)
  
              except:  # pylint:disable=bare-except;We cannot let this background thread die until we are told to stop()
                  self._logger.exception("Error inside background workqueue thread")
docs: The target routine called to start thread activity.