如何使用键盘库在.is_pressed中使用组合键？

import keyboard

# 定义标志变量
ctrl_pressed = False
s_pressed = False

def on_key_event(event):
    global ctrl_pressed, s_pressed
    
    if event.event_type == keyboard.KEY_DOWN:
        # 检测 Ctrl 键按下
        if event.name == 'ctrl':
            ctrl_pressed = True
        # 检测 S 键按下
        if event.name == 's':
            s_pressed = True
    elif event.event_type == keyboard.KEY_UP:
        # 检测 Ctrl 键释放
        if event.name == 'ctrl':
            ctrl_pressed = False
        # 检测 S 键释放
        if event.name == 's':
            s_pressed = False
        
        # 检测组合键 Ctrl + S
        if ctrl_pressed and s_pressed:
            # 执行相应操作
            print("Ctrl + S 组合键被按下")
            # 这里可以添加你的代码逻辑
    
# 注册回调函数，监听键盘事件
keyboard.on_press_key('ctrl', on_key_event)
keyboard.on_press_key('s', on_key_event)
keyboard.on_release_key('ctrl', on_key_event)
keyboard.on_release_key('s', on_key_event)

# 保持监听状态
keyboard.wait()