class_docstr: Tests for TopKUniquesSketchStatsGenerator.
class_docstr_tok: ["Tests","for","TopKUniquesSketchStatsGenerator","."]
code: def test_topk_uniques_sketch_zero_row(self):
      batches = [
          pa.RecordBatch.from_arrays(
              [pa.array([], type=pa.list_(pa.binary()))], ["f1"]
          )
      ]
      expected_result = {}
      generator = sketch_generator.TopKUniquesSketchStatsGenerator(
          num_top_values=4, num_rank_histogram_buckets=3
      )
      self.assertCombinerOutputEqual(
          batches, generator, expected_result
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  from absl.testing import parameterized
  import pyarrow
  from tensorflow_data_validation import types
  from tensorflow_data_validation.statistics.generators import top_k_uniques_sketch_stats_generator
  from tensorflow_data_validation.utils import test_util
  from tensorflow_data_validation.utils.example_weight_map import ExampleWeightMap
  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 5 for calling the TopKUniquesSketchStatsGeneratorTest obj's underlying member method code with example usage: obj.test_topk_uniques_sketch_zero_row() without return types