multiclass ROC AUC curve
def multiclass_roc_auc_score(y_test, y_pred, average="macro"):
lb = LabelBinarizer()
lb.fit(y_test)
y_test = lb.transform(y_test)
y_pred = lb.transform(y_pred)
return roc_auc_score(y_test, y_pred, average=average)