tf2无法从检查点还原

Question

我正在构建seq2seq模型，并使用检查点保存编码器和解码器：

checkpoint_dir = './training_checkpoints'
checkpoint_prefix = os.path.join(checkpoint_dir, "ckpt")
checkpoint = tf.train.Checkpoint(optimizer=optimizer,
                                 encoder=encoder,
                                 decoder=decoder)
checkpoint.save(file_prefix = checkpoint_prefix)

但是，当我尝试从检查点目录还原时，它似乎不起作用。

checkpoint_dir = './training_checkpoints'
checkpoint_prefix = os.path.join(checkpoint_dir, "ckpt")
checkpoint = tf.train.Checkpoint(optimizer=optimizer,
                                 encoder=encoder,
                                 decoder=decoder)
checkpoint.restore(tf.train.latest_checkpoint(checkpoint_dir))

该如何解决？谢谢〜