如何判断代理IP是否有效

import requests

url = 'http://icanhazip.com'
proxy = {'http':'60.179.200.53:3000'}
proxy = {'http':'125.123.155.156:3000'}
proxy = {'http':'111.222.141.127:8118'} #广东深圳
proxy = {'http':'117.69.170.45:4216'}
proxy = {'http':'222.88.158.34:8060'} #河南安阳
proxy = {'http':'113.119.47.199:8118'} #广东广州

resp = requests.get(url,proxies=proxy).text

print(resp)