code: def _cull(self):
          
          right_now = time.time()
  
          cull_from = -1
          for index in range(len(self._call_times)):
              if right_now - self._call_times[index].time >= 1.0:
                  cull_from = index
                  self._outstanding_calls -= self._call_times[index].num_calls
              else:
                  break
  
          if cull_from > -1:
              self._call_times = self._call_times[cull_from + 1:]
docs: Remove calls more than 1 second old from the queue.