AttributeError:无法在拆分MNIST数据集时设置属性

from sklearn.datasets import fetch_openml
from sklearn.model_selection import train_test_split

# 加载MNIST数据集
mnist = fetch_openml('mnist_784', version=1)
X, y = mnist.data, mnist.target

# 拆分数据集
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)

# 现在你可以使用X_train, X_test, y_train, y_test进行训练和测试