code: def _merge_shards(
      shards: Iterable[statistics_pb2.DatasetFeatureStatisticsList],
  ) -> statistics_pb2.DatasetFeatureStatisticsList:
      """Helper to merge shards for test comparison."""
  
      def _flatten(shards):
          for statistics_list in shards:
              for dataset in statistics_list.datasets:
                  yield dataset
  
      return merge_util.merge_dataset_feature_statistics(
          _flatten(shards)
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import copy
  import sys
  from typing import Iterable
  import unittest
  from absl.testing import absltest
  from absl.testing import parameterized
  import apache_beam
  from apache_beam.testing import util
  import numpy
  import pyarrow
  from tensorflow_data_validation.statistics import stats_impl
  from tensorflow_data_validation.statistics import stats_options
  from tensorflow_data_validation.statistics.generators import cross_feature_stats_generator
  from tensorflow_data_validation.statistics.generators import stats_generator
  from tensorflow_data_validation.utils import slicing_util
  from tensorflow_data_validation.utils import test_util
  from tfx_bsl.arrow import array_util
  from tfx_bsl.arrow import table_util
  from tfx_bsl.public.proto import slicing_spec_pb2
  from tfx_bsl.statistics import merge_util
  from google.protobuf import text_format
  from tensorflow.python.util.protobuf import compare
  from tensorflow_metadata.proto.v0 import schema_pb2
  from tensorflow_metadata.proto.v0 import statistics_pb2
label_desc: Use image node_id 2 for calling a global function with example usage: _merge_shards(shards) and returns: merge_util