code: def _create_combiner(
      self,
      dp_metrics=(pipeline_dp.Metrics.COUNT,),
      public_partitions=False,
      weight_fn=cross_partition_combiners.equal_weight_fn,
  ):
      return cross_partition_combiners.CrossPartitionCombiner(
          dp_metrics, public_partitions, weight_fn
      )
  
imports: from absl.testing import absltest
  from absl.testing import parameterized
  import dataclasses
  import math
  from unittest import mock
  from unittest.mock import patch
  from analysis import metrics
  from analysis import cross_partition_combiners
  import pipeline_dp
label_desc: Use image node_id 1 for calling the CrossPartitionCombiner obj's underlying member method code with example usage: obj._create_combiner(dp_metrics, public_partitions, weight_fn) and returns: cross_partition_combiners