class_docstr: Dummy beam dataset.
class_docstr_tok: ["Dummy","beam","dataset","."]
code: def _info(self):
      return datasets.DatasetInfo(
          features=datasets.Features(
              {"a": datasets.Sequence({"b": datasets.Value("string")})}
          ),
          # No default supervised_keys.
          supervised_keys=None,
      )
  
imports: import os
  import tempfile
  from functools import partial
  from unittest import TestCase
  from unittest.mock import patch
  import datasets
  import datasets.config
  from .utils import require_beam
label_desc: Use image node_id 1 for calling the NestedBeamDataset obj's underlying member method code with example usage: obj._info() and returns: datasets