python 转换 Javascript %u 字符串为python unicode的代码

import re
import codecs
pattern = re.compile('%u[0-9A-Z]{4}')

n = codecs.open('d:\\new.txt', 'w', 'utf-8') 
with open('d:\\p', 'r') as f:
 for l in f:
  for i in pattern.findall(l):
   l = l.replace(i, unichr(int(i[2:], 16)))
   n.write(l)

n.close()