code: def test_rej_opt_clf_fit(new_ROC, old_ROC):
      """Test RejectOptionClassifierCV fit matches old."""
      assert np.isclose(
          new_ROC.best_estimator_.threshold,
          old_ROC.classification_threshold,
          atol=0.05,
      )
      assert np.isclose(
          new_ROC.best_estimator_.margin, old_ROC.ROC_margin, atol=0.05
      )
  
file_path: AIF360/tests/sklearn/test_reject_option_classification.py
imports: from itertools import product
  import numpy
  import pandas
  import pytest
  from sklearn.linear_model import LogisticRegression
  from sklearn.model_selection import train_test_split
  from sklearn.metrics import make_scorer
  from aif360.algorithms.postprocessing import RejectOptionClassification
  from aif360.sklearn.postprocessing import RejectOptionClassifier, RejectOptionClassifierCV, PostProcessingMeta
  from aif360.sklearn.metrics import generalized_entropy_error
label_desc: Use image node_id 4 for calling a global function with example usage: test_rej_opt_clf_fit(new_ROC, old_ROC) without return types