class_docstr: CombineFn to combine dictionaries generated by different evaluators.
code: def _merge(
      self, accumulator: Dict[str, Any], output_dict: Dict[str, Any]
  ) -> None:
      intersection = set(accumulator) & set(output_dict)
      if intersection:
          raise ValueError(
              "Dictionaries generated by different evaluators should have "
              "different keys, but keys %s appeared in the output of multiple "
              "evaluators" % intersection
          )
      accumulator.update(output_dict)
  
file_path: model-analysis/tensorflow_model_analysis/evaluators/evaluator.py
imports: from typing import Any, Dict, Iterable, List, NamedTuple, Optional
  import apache_beam
  from tensorflow_model_analysis.extractors import extractor
label_desc: Use image node_id 2 for calling the _CombineEvaluationDictionariesFn obj's underlying member method code with example usage: obj._merge(accumulator, output_dict) without return types