google.adk.evaluation.metric_evaluator_registry.MetricEvaluatorRegistry
https://github.com/google/adk-python/blob/v1.23.0/src/google/adk/evaluation/metric_evaluator_registry.py#L47
クラス変数 _registry: dict[str, tuple[type[Evaluator], MetricInfo]] = {}
google.adk.evaluation.evaluator.Evaluator
def get_evaluator(self, eval_metric: EvalMetric) -> Evaluator
def register_evaluator(self, metric_info: MetricInfo, evaluator: type[Evaluator])