class_docstr: CombineFn to create query examples for each query id.
  
  Note that this assumes the number of examples for each query ID is small
  enough to fit in memory.
code: def merge_accumulators(
      self, accumulators: Iterable[List[types.Extracts]]
  ) -> List[types.Extracts]:
      accumulators = iter(accumulators)
      result = next(accumulators)
      for acc in accumulators:
          result.extend(acc)
      return result
  
imports: from typing import Any, Dict, Iterable, Iterator, List, Optional, Tuple
  import apache_beam
  import numpy
  import tensorflow
  from tensorflow_model_analysis import constants
  from tensorflow_model_analysis.api import types
  from tensorflow_model_analysis.eval_saved_model import constants
  from tensorflow_model_analysis.eval_saved_model import encoding
  from tensorflow_model_analysis.eval_saved_model import util
  from tensorflow_model_analysis.evaluators import evaluator
  from tensorflow_model_analysis.evaluators.query_metrics import query_types
  from tensorflow_model_analysis.extractors import extractor
  from tensorflow_model_analysis.extractors import slice_key_extractor
label_desc: Use image node_id 4 for calling the CreateQueryExamples obj's underlying member method code with example usage: obj.merge_accumulators(accumulators) and returns: result