Python 正则表达式取值

import re

class Retest:
   def __init__(self,string,path):
      self.string = string
      self.path = path

   def retest(self):
      res = re.search(self.string,self.path,flags=0).group()
      # res.group()
      print res
      return

if __name__ == '__main__':
    a = 'helloworld'
    b = 'he(.+)ld'
　　c = Retest(b,a)
　　c.retest()