python获取url顶级域名: 支持 http://baidu.com www.baidu.com http://www.baidu.com 后缀支持: ".com", ".cn", ".com.cn", ".gov", ".net", ".edu.cn", ".net.cn", ".org.cn", ".co.jp", ".gov.cn", ".co.uk", "ac.cn", ".edu", ".tv",".info", ".ac", ".ag", ".am", ".at", ".be",