r - R Keras EarlyStopping 无法将类型环境强制为整数类型的向量

Question

使用 R Keras 开发深度学习，我想实现 earlystopping 回调，但它显示错误：Error in as.integer(verbose) : cannot coerce type 'environment' to vector of type 'integer'

R代码：

# Compiling the model
model %>% compile(loss = "categorical_crossentropy",
                  optimizer = "adam",
                  
                  metrics = c("accuracy"))

history <- model %>% 
  fit(x_train,
      y_train,
      epoch = 250,
      batch_size = 32,
      callback_early_stopping(monitor = "val_loss", 
                              min_delta = 0.001, 
                              patience = 5,
                              restore_best_weights = TRUE,
                              verbose = 1),
      validation_split = 0.2
      )

知道有什么问题吗？谢谢。