docstr: Tests generator invalidation whith empty natural language domain.
docstr_tok: ["Tests","generator","invalidation","whith","empty","natural","language","domain","."]
code: def test_nl_generator_invalidation_check_empty_nld(self):
      """Tests generator invalidation whith empty natural language domain."""
      generator = nlsg.NLStatsGenerator(self._schema, None, 0, 0, 0)
      generator.setup()
      accumulator = generator.create_accumulator()
      self.assertFalse(accumulator.invalidate)
      valid_input = pa.array([[0], [1]])
      accumulator = generator.add_input(
          accumulator, self._int_nlp_feature_empty_domain, valid_input
      )
      self.assertTrue(accumulator.invalidate)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tempfile
  from absl.testing import absltest
  import pyarrow
  from tensorflow_data_validation import types
  from tensorflow_data_validation.statistics.generators import natural_language_stats_generator
  from tensorflow_data_validation.utils import test_util
  from google.protobuf import text_format
  from tensorflow_metadata.proto.v0 import schema_pb2
  from tensorflow_metadata.proto.v0 import statistics_pb2
label_desc: Use image node_id 6 for calling the NaturalLanguageStatsGeneratorTest obj's underlying member method code with example usage: obj.test_nl_generator_invalidation_check_empty_nld() without return types