code: def test_partial_stats_iadd(self):
      stats = nlsg._PartialNLStats(
          matched=4, considered=10, invalidate=False
      )
      stats2 = nlsg._PartialNLStats(
          matched=2, considered=12, invalidate=False
      )
  
      stats += stats2
      self.assertEqual(6, stats.matched)
      self.assertEqual(22, stats.considered)
      self.assertEqual(False, stats.invalidate)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  import pyarrow
  from tensorflow_data_validation.statistics.generators import natural_language_domain_inferring_stats_generator
  from tensorflow_data_validation.utils import test_util
  from typing import Text
  from tensorflow_metadata.proto.v0 import statistics_pb2
label_desc: Use image node_id 1 for calling the NaturalLanguageStatsGeneratorTest obj's underlying member method code with example usage: obj.test_partial_stats_iadd() without return types