tensorflow2.0添加checkpoint报错

问题：ValueError: Checkpoint was expecting a trackable object (an object derived from TrackableBase)
解决办法：自定义的类需要继承带有Trackable的父类，例如 tf.keras.Model
可参考：https://zhuanlan.zhihu.com/p/73575776
https://blog.csdn.net/TeFuirnever/article/details/102722176