报错：TypeError: The added layer must be an instance of class Layer.

解决方法：
点击activation,组合键alt+enter，然后选择Convert tuple to list

选择Convert tuple to set会报错

TypeError: The added layer must be an instance of class Layer. Found: {
     <tensorflow.python.keras.layers.core.Flatten object at 0x0000023092C7C588>, <tensorflow.python.keras.layers.core.Dense object at 0x00000230944B02E8>, <tensorflow.python.keras.layers.core.Dense object at 0x00000230944B05F8>}