code: def test_create_accumulator_empty_data(self):
      sparse, dense = self._create_combiner().create_accumulator(())
      self.assertEqual(sparse, ([0], [0], [0]))
      self.assertIsNone(dense)
  
imports: import dataclasses
  import numpy
  from absl.testing import absltest
  from absl.testing import parameterized
  from unittest.mock import patch
  from typing import Tuple
  import pipeline_dp
  from analysis import per_partition_combiners
  from analysis import metrics
  from analysis.tests import common
label_desc: Use image node_id 2 for calling the UtilityAnalysisCompoundCombinerTest obj's underlying member method code with example usage: obj.test_create_accumulator_empty_data() without return types