code: def test_rej_opt_clf_postproc_meta(new_adult, new_ROC):
      """Test PostProcessingMeta pipeline with RejectOptionClassifierCV."""
      X, y, sample_weight = new_adult
      lr = LogisticRegression(solver="lbfgs", max_iter=500)
      lr.fit(X, y, sample_weight=sample_weight)
      pp = PostProcessingMeta(
          lr,
          RejectOptionClassifierCV(
              "sex", scoring="statistical_parity", step=0.1, n_jobs=-1
          ),
          prefit=True,
          random_state=1234,
      )
      pp.fit(X, y)
      assert pp.postprocessor_.best_params_ == new_ROC.best_params_
      assert (
          pp.postprocessor_.cv_results_["mean_test_bal_acc"]
          == new_ROC.cv_results_["mean_test_bal_acc"]
      ).all()
  
      pp.set_params(prefit=False).fit(X, y, sample_weight=sample_weight)
  
      (
          X_train,
          X_test,
          y_train,
          y_test,
          sw_train,
          sw_test,
      ) = train_test_split(
          X, y, sample_weight, train_size=0.75, random_state=1234
      )
      lr.fit(X_train, y_train, sample_weight=sw_train)
      y_pred = pd.DataFrame(
          lr.predict_proba(X_test), index=y_test.index
      )
      new_ROC.fit(y_pred, y_test)
      assert (lr.coef_ == pp.estimator_.coef_).all()
      assert pp.postprocessor_.best_params_ == new_ROC.best_params_
      assert (
          pp.postprocessor_.cv_results_["mean_test_bal_acc"]
          == new_ROC.cv_results_["mean_test_bal_acc"]
      ).all()
  
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 8 for calling a global function with example usage: test_rej_opt_clf_postproc_meta(new_adult, new_ROC) without return types