class_docstr: CombineFn to combine dictionaries generated by different evaluators.
code: def create_accumulator(self) -> Dict[str, Any]:
      return {}
  
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 1 for calling the _CombineEvaluationDictionariesFn obj's underlying member method code with example usage: obj.create_accumulator() and returns: dict