from sklearn.model_selection import RandomizedSearchCV,GridSearchCV
import xgboost

classifier=xgboost.XGBClassifier()
random_search=RandomizedSearchCV(classifier,param_distributions=params,n_iter=5,scoring='roc_auc',n_jobs=-1,cv=5,verbose=3)
random_search.best_estimator_

. AttributeError：“RandomizedSearchCV”对象没有属性“best_estimator_”