在使用R Keras包时，如何在R中获取每次调优运行时使用的标志值？

library(keras)

# 自定义回调函数
CustomCallback <- keras::Callback$from_config(function(config) {
  keras::Callback$new()
})

# 重写on_epoch_end()方法
CustomCallback$on_epoch_end <- function(epoch, logs = NULL) {
  # 获取标志值
  flags <- self$params$flags
  # 打印标志值
  print(flags)
}

# 创建模型
model <- keras::Sequential()
model$add(keras::Dense(units = 64, activation = "relu", input_shape = c(10,)))
model$add(keras::Dense(units = 1, activation = "sigmoid"))

# 编译模型
model$compile(optimizer = "adam", loss = "binary_crossentropy", metrics = c("accuracy"))

# 设置回调函数
callbacks <- list(CustomCallback)

# 训练模型
model$fit(x_train, y_train, epochs = 10, batch_size = 32, callbacks = callbacks)