code: def test_add_accumulators_probabilities_moments(self):
      acc1 = self._create_accumulator(
          probabilities=(0.1, 0.2), moments=None
      )
      moments = combiners.SumOfRandomVariablesMoments(
          count=10, expectation=5, variance=50, third_central_moment=1
      )
      acc2 = self._create_accumulator(
          probabilities=None, moments=moments
      )
      acc = combiners._merge_partition_selection_accumulators(
          acc1, acc2
      )
  
      # Test that the result has moments.
      probabilities, moments = acc
      self.assertIsNone(probabilities)
      self.assertEqual(12, moments.count)
  
      # Test that no type is np.float64
      self.assertTrue(_check_none_are_np_float64(acc))
  
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 5 for calling the PartitionSelectionTest obj's underlying member method code with example usage: obj.test_add_accumulators_probabilities_moments() without return types