残差网络(ResNet)

http://zh-v2.d2l.ai/chapter_convolutional-modern/resnet.html

我想问一下class ResnetBlock模块的tensorflow的实现,我使用书中代码时,使用model.fit训练前会提示说
WARNING:tensorflow:Model failed to serialize as JSON. Ignoring… Layer ResnetBlock has arguments in __init__ and therefore must override get_config.
训练中保存模型时会提示下面错误信息:
NotImplementedError: Layer ResnetBlock has arguments in __init__ and therefore must override get_config.
是否书中的实现有问题?