code: def test_get_nonexistent_natural_language_statistics_dataframes(self):
      statistics = text_format.Parse(
          """
      datasets {
        num_examples: 3
        features {
          name: 'a'
          type: BYTES
        }
      }
      """,
          statistics_pb2.DatasetFeatureStatisticsList(),
      )
      actual = display_util.get_natural_language_statistics_dataframes(
          statistics
      )
      self.assertIsNone(actual)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from typing import Any, Dict
  from absl.testing import absltest
  from absl.testing import parameterized
  from google.protobuf import text_format
  import pandas
  from tensorflow_data_validation import constants
  from tensorflow_data_validation import types
  from tensorflow_data_validation.skew.protos import feature_skew_results_pb2
  from tensorflow_data_validation.utils import display_util
  from tensorflow_data_validation.utils import test_util
  from tensorflow_metadata.proto.v0 import anomalies_pb2
  from tensorflow_metadata.proto.v0 import schema_pb2
  from tensorflow_metadata.proto.v0 import statistics_pb2
label_desc: Use image node_id 15 for calling the DisplayUtilTest obj's underlying member method code with example usage: obj.test_get_nonexistent_natural_language_statistics_dataframes() without return types