Keras:保存定义为类的模型将引发NotImplementedError

from keras.models import Model
from keras.layers import Input, Dense

# 定义模型的输入层
inputs = Input(shape=(10,))

# 定义模型的其他层
x = Dense(64, activation='relu')(inputs)
outputs = Dense(1, activation='sigmoid')(x)

# 创建模型
model = Model(inputs=inputs, outputs=outputs)

# 保存模型
model.save('model.h5')

# 加载模型
loaded_model = load_model('model.h5')

import json

# 保存模型结构
model_json = model.to_json()
with open('model.json', 'w') as json_file:
    json_file.write(model_json)

# 保存模型权重
model.save_weights('model_weights.h5')

# 加载模型结构
with open('model.json', 'r') as json_file:
    loaded_model_json = json_file.read()
loaded_model = model_from_json(loaded_model_json)

# 加载模型权重
loaded_model.load_weights('model_weights.h5')