调用预测时，Sklearn Imputer Pipeline在X_test值上运行？

Question

如果我在Sklearn中有这样的管道：

steps = [('imputation', Imputer(missing_values='NaN', strategy='most_frequent', axis=0)),
            ('Ridge', Ridge(alpha=0.1, normalize=True))]
pipeline = Pipeline(steps)
pipeline.fit(X, y)

# Will the imputer be run on the X_test values here?
pred = pipeline.predict(X_test)

是否可以在X_test值上运行imputer？