在 Google colab 中运行此 code 时遇到此错误。

错误是：

InvalidArgumentError                      Traceback (most recent call last)
<ipython-input-14-67951c7b20d5> in <module>()
     22 
     23 model3 = get_model3()
---> 24 model3.fit(wrap_generator3(train_generator3),steps_per_epoch=train_generator3.samples/train_generator3.batch_size,epochs=20)
     25 #model3.fit_generator(generator=train_generator3,epochs=20)

7 frames
/usr/local/lib/python3.6/dist-packages/tensorflow/python/client/session.py in __init__(self,session,callable_options)
   1468       try:
   1469         self._handle = tf_session.TF_SessionmakeCallable(
-> 1470             session._session,options_ptr)
   1471       finally:
   1472         tf_session.TF_DeleteBuffer(options_ptr)

InvalidArgumentError: Requested tensor connection from unknown node: "dense_8_target:0".

我如何解决这个问题？ 谁能帮我？ 谢谢