如果某个URL可达，如何停止python程序

import requests
import sys

def check_url_reachable(url):
    try:
        response = requests.head(url)
        if response.status_code == 200:
            return True
        else:
            return False
    except requests.exceptions.RequestException:
        return False

if check_url_reachable("http://example.com"):
    print("URL is reachable. Stopping the program.")
    sys.exit()
else:
    print("URL is not reachable. Continuing the program.")
    # 继续执行其他操作