code: def extract_output(self, accumulator):
      raise NotImplementedError(
          "extract_output intentionally not implement to verify behavior. We "
          "would like to be able to mock a combine_fn and then call "
          "combine_fn.extract_output.assert_not_called()."
      )
  
imports: import functools
  from absl.testing import absltest
  import apache_beam
  from apache_beam.testing import util
  from tensorflow_model_analysis.api import types
  from tensorflow_model_analysis.evaluators import confidence_intervals_util
  from tensorflow_model_analysis.evaluators import jackknife
  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 ListCombineFnExtractOutputNotImplemented obj's underlying member method code with example usage: obj.extract_output(accumulator) without return types