曹建老师的LSTM预测股票的源代码在我的电脑上运行报错，是怎么回事呀？

Question

Traceback (most recent call last):
  File "d:\Python\作业\Tensorflow代码\class6\p15_rnn_onehot_1pre1.py", line 47, in <module>
    history = model.fit(x_train, y_train, batch_size=32, epochs=100, callbacks=[cp_callback])
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training.py", line 728, in fit
    use_multiprocessing=use_multiprocessing)
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py", line 224, in fit
    distribution_strategy=strategy)
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py", line 547, in _process_training_inputs
    use_multiprocessing=use_multiprocessing)
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py", line 594, in _process_inputs
    steps=steps)
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training.py", line 2433, in _standardize_user_data
    self._compile_from_inputs(all_inputs, y_input, x, y)
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training.py", line 2668, in _compile_from_inputs
    experimental_run_tf_function=self._experimental_run_tf_function)
  File "E:\Python\lib\site-packages\tensorflow_core\python\training\tracking\base.py", line 457, in _method_wrapper
    result = method(self, *args, **kwargs)
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training.py", line 343, in compile
    endpoint.create_training_target(t, run_eagerly=self.run_eagerly)
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\engine\training.py", line 3038, in create_training_target
    self.loss_fn, K.dtype(self.output))
  File "E:\Python\lib\site-packages\tensorflow_core\python\keras\backend.py", line 1249, in dtype
    return x.dtype.base_dtype.name
AttributeError: 'NoneType' object has no attribute 'dtype'

Answer 1

'NoneType' object has no attribute 'dtype'，没有dtype属性，是不是版本问题呢？