python readline 读文件

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

import time

class Readfile(object):
        '''读取/etc/passwd一行一行读取'''
        def file(chef):
                file = open('/etc/passwd')
                c = file.readlines()
                num = 1
                for i in c:
                        print num,i.strip()
                        num = num + 1
                        time.sleep(1)
                print 'read done
if  __name__=='__main__':
    f = Readfile()
    f.file()