code: def detect_iter(self, det_iter, show_timer=False):
          
          num_images = det_iter._size
          if not isinstance(det_iter, mx.io.PrefetchingIter):
              det_iter = mx.io.PrefetchingIter(det_iter)
          start = timer()
          detections = self.mod.predict(det_iter).asnumpy()
          time_elapsed = timer() - start
          if show_timer:
              logging.info("Detection time for {} images: {:.4f} sec".format(
                  num_images, time_elapsed))
          result = Detector.filter_positive_detections(detections)
          return result
docs: detect all images in iterator
  
          Parameters:
          ----------
          det_iter : DetIter
              iterator for all testing images
          show_timer : Boolean
              whether to print out detection exec time
  
          Returns:
          ----------
          list of detection results