def is_topk_evaluator(evaluator_keys):
  """Are these evaluator keys from TopK evaluator?"""
  return (len(evaluator_keys) == 5 and
          evaluator_keys[0] == 'top_1' and
          evaluator_keys[1] == 'top_2' and
          evaluator_keys[2] == 'top_3' and
          evaluator_keys[3] == 'top_4' and
          evaluator_keys[4] == 'top_5')