def _update_groundtruth_statistics(self, groundtruth_class_tuples):
    """Updates grouth truth statistics.

    Args:
      groundtruth_class_tuples: A numpy array of structures shape [M, 1],
          representing  the class labels of the corresponding bounding boxes and
          possibly additional classes.
    """
    self._num_gt_instances += groundtruth_class_tuples.shape[0]
    self._num_gt_imgs += 1
    for relation_field_value in np.unique(groundtruth_class_tuples['relation']):
      if relation_field_value not in self._num_gt_instances_per_relationship:
        self._num_gt_instances_per_relationship[relation_field_value] = 0
      self._num_gt_instances_per_relationship[relation_field_value] += np.sum(
          groundtruth_class_tuples['relation'] == relation_field_value)
Updates grouth truth statistics.

    Args:
      groundtruth_class_tuples: A numpy array of structures shape [M, 1],
          representing  the class labels of the corresponding bounding boxes and
          possibly additional classes.
    
inference_api/src/main/object_detection/utils/vrd_evaluation.py