code: def _validate_match_stats(self, diff_dir):
      diff_path = os.path.join(diff_dir, executor.MATCH_STATS_FILE_NAME)
      count = len(
          list(feature_skew_detector.match_stats_iterator(diff_path))
      )
      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 4 for calling the ExecutorTest obj's underlying member method code with example usage: obj._validate_match_stats(diff_dir) without return types