# Import DecisionTreeClassifier
from sklearn.tree import DecisionTreeClassifier
# Import AdaBoostClassifier
from sklearn.ensemble import AdaBoostClassifier
# Instantiate dt
dt = DecisionTreeClassifier(max_depth=2, random_state=1)
# Instantiate ada
ada = AdaBoostClassifier(base_estimator=dt, n_estimators=180, random_state=1)
# Fit ada to the training set
ada.fit(X_train, y_train)
# Compute the probabilities of obtaining the positive class
y_pred_proba = ada.predict_proba(X_test)[:,1]
# Import roc_auc_score
from sklearn.metrics import roc_auc_score
# Evaluate test-set roc_auc_score
ada_roc_auc = roc_auc_score(y_test, y_pred_proba)
# Print roc_auc_score
print('ROC AUC score: {:.2f}'.format(ada_roc_auc))