code: def __call__(self, predict, label, **kwargs) -> Dict:
      predict = self.to_np_format(predict)
      label = self.to_np_format(label)
      r2 = r2_score(label, predict)
      return EvalResult(self.metric_name, r2)
  
file_path: FATE/python/fate/ml/evaluation/regression.py
imports: from typing import Dict
  import numpy
  from fate.ml.evaluation.metric_base import Metric
  from sklearn.metrics import mean_squared_error, mean_absolute_error, r2_score
  from fate.ml.evaluation.metric_base import EvalResult
label_desc: Use image node_id 1 for calling the R2Score obj's underlying member method code with example usage: obj.__call__(predict, label) and returns: EvalResult