在使用TensorFlow2.0以上的版本,读取历史acc时出现这个问题,需要将acc改为accuracy,将val_acc
改为val_accuracy
train_loss = history.history['loss'][0]
train_acc = history.history['accuracy'][0]
val_loss = history.history['val_loss'][0]
val_acc = history.history['val_accuracy'][0]