code: def _read_annotations(self, config, dataset_type):
      annotations = config.get("annotations", {}).get(dataset_type, [])
  
      # User can pass a single string as well
      if isinstance(annotations, str):
          annotations = [annotations]
  
      if len(annotations) == 0:
          warnings.warn(
              "Dataset type {} is not present or empty in "
              + "annotations of dataset config or either annotations "
              + "key is not present. Returning None. "
              + "This dataset won't be used.".format(dataset_type)
          )
          return None
      return annotations
  
imports: import collections
  import os
  import typing
  import warnings
  from copy import deepcopy
  import mmf.utils.download
  import torch
  from mmf.datasets.base_dataset_builder import BaseDatasetBuilder
  from mmf.datasets.concat_dataset import MMFConcatDataset
  from mmf.datasets.subset_dataset import MMFSubset
  from mmf.utils.configuration import get_global_config, get_mmf_env, get_zoo_config
  from mmf.utils.general import get_absolute_path
  from omegaconf import open_dict
label_desc: Use image node_id 15 for calling the MMFDatasetBuilder obj's underlying member method code with example usage: obj._read_annotations(config, dataset_type) and returns: annotations, None