如何保存sklearn FeatureUnion？

import pickle

from sklearn.pipeline import FeatureUnion
from sklearn.feature_extraction.text import CountVectorizer
from sklearn.feature_extraction.text import TfidfTransformer

# 假设有两个特征提取器
count_vectorizer = CountVectorizer()
tfidf_transformer = TfidfTransformer()

# 创建FeatureUnion对象
feature_union = FeatureUnion([
    ('count_vectorizer', count_vectorizer),
    ('tfidf_transformer', tfidf_transformer)
])

# 进行训练
feature_union.fit(X)

# 保存FeatureUnion对象
with open('feature_union.pkl', 'wb') as f:
    pickle.dump(feature_union, f)

# 加载保存的FeatureUnion对象
with open('feature_union.pkl', 'rb') as f:
    feature_union = pickle.load(f)