【python】regexでURLを認識

#!/usr/bin/python
# -*- coding:utf-8 -*-

import re


url = "http://www.sankei.com/economy/news/160923/ecn1609230018-n1.html"

pattern = re.compile("^(https?|ftp)://www\.sankei\.com*?")

m = pattern.search(url)
if m:
    print(url)
else:
    print(None)