def modify_state_for_body(s, body):
            s.layers['segmentation'].segments = frozenset([body.segment_id])
            s.voxel_coordinates = body.bbox_start + body.bbox_size // 2
def _update_height(self, height_diff):
    if self._items_total_height is None:
      self._items_total_height = self.get_allocation().height