code: def test_R2Score(self):
      r2_metric = R2Score()
      predict = np.random.random_sample(1000) * 10
      label = np.random.random_sample(1000) * 10
      result = r2_metric(predict, label)
      self.assertEqual(result.metric_name, "r2_score")
      self.assertAlmostEqual(
          result.result, r2_score(label, predict), places=7
      )
  
file_path: FATE/python/fate/ml/evaluation/test/test_reg_metric.py
imports: import unittest
  import numpy
  from sklearn.metrics import mean_squared_error, mean_absolute_error, r2_score
  from fate.ml.evaluation.regression import *
label_desc: Use image node_id 4 for calling the TestMetric obj's underlying member method code with example usage: obj.test_R2Score() without return types