如何在tensorflow python中打印训练过程中的训练损失

import tensorflow as tf

# 定义模型
model = tf.keras.Sequential([...])

# 定义训练数据
train_data = [...]

# 定义训练标签
train_labels = [...]

model.compile(optimizer='adam', loss='sparse_categorical_crossentropy', metrics=['accuracy'])

class PrintLossCallback(tf.keras.callbacks.Callback):
    def on_epoch_end(self, epoch, logs=None):
        print(f"Epoch {epoch+1}: Loss = {logs['loss']:.4f}")

# 创建回调对象
print_loss_callback = PrintLossCallback()

model.fit(train_data, train_labels, epochs=10, callbacks=[print_loss_callback])