code: def extract_output(
      self,
      accumulator: confidence_intervals_util.SampleCombineFn.SampleAccumulator,
  ) -> confidence_intervals_util.SampleCombineFn.SampleAccumulator:
      return self._validate_accumulator(accumulator)
  
file_path: model-analysis/tensorflow_model_analysis/evaluators/confidence_intervals_util_test.py
imports: from absl.testing import absltest
  from absl.testing import parameterized
  import apache_beam
  from apache_beam.testing import util
  import numpy
  from numpy import testing
  from tensorflow_model_analysis.evaluators import confidence_intervals_util
  from tensorflow_model_analysis.metrics import binary_confusion_matrices
  from tensorflow_model_analysis.metrics import metric_types
label_desc: Use image node_id 1 for calling the _ValidateSampleCombineFn obj's underlying member method code with example usage: obj.extract_output(accumulator) and returns: self