code: def _validate_skew_pairs(self, diff_dir, expect_matches):
      diff_path = os.path.join(diff_dir, executor._SAMPLE_FILE_NAME)
      self.assertNotEmpty(fileio.glob(diff_path + "*-of-*"))
      count = 0
      for _ in feature_skew_detector.skew_pair_iterator(diff_path):
          count += 1
      if not expect_matches:
          self.assertEqual(count, 0)
      else:
          self.assertGreater(count, 0)
  
imports: import os
  import tempfile
  from absl.testing import absltest
  from absl.testing import parameterized
  import tensorflow_data_validation
  from tensorflow_data_validation.skew import feature_skew_detector
  from tfx.components.example_diff import executor
  from tfx.dsl.io import fileio
  from tfx.proto import example_diff_pb2
  from tfx.types import artifact_utils
  from tfx.types import standard_artifacts
  from tfx.types import standard_component_specs
  from tfx.utils import json_utils
  from google.protobuf import text_format
label_desc: Use image node_id 3 for calling the ExecutorTest obj's underlying member method code with example usage: obj._validate_skew_pairs(diff_dir, expect_matches) without return types