有没有更快的方法来获得MNIST数据集的本地二进制模式？

import tensorflow as tf

(train_images, train_labels), (test_images, test_labels) = tf.keras.datasets.mnist.load_data()

with open('train_images.bin', 'wb') as f:
    f.write(train_images.tobytes())

with open('train_labels.bin', 'wb') as f:
    f.write(train_labels.tobytes())

with open('test_images.bin', 'wb') as f:
    f.write(test_images.tobytes())

with open('test_labels.bin', 'wb') as f:
    f.write(test_labels.tobytes())