code: def _download_ann(self):
      pass
  
imports: import os
  from lavis.common.registry import registry
  from lavis.datasets.builders.base_dataset_builder import BaseDatasetBuilder
  from lavis.datasets.datasets.image_text_pair_datasets import ImageTextPairDataset, ImageTextPairInstructDataset
  from lavis.datasets.datasets.laion_dataset import LaionDataset, LaionInstructDataset
label_desc: Use image node_id 1 for calling the Laion2BMultiBuilder obj's underlying member method code with example usage: obj._download_ann() without return types