在实际的运用中，每次登陆的时间不会是一个固定值，如何把老师写的2015-0511改成系统时间？

#!/usr/bin/python
import os
import os.path
import ConfigParser
class student_info(object):
    def __init__(self,recordfile):
        self.logfile=recordfile
        self.cfg=ConfigParser.ConfigParser()
    def cfg_load(self):
        self.cfg.read(self.logfile)
    def cfg_dump(self):
        se_list=self.cfg.sections()
        print('============>')
        for se in se_list:
            print(se)
            print(self.cfg.items(se))
        print('<============')
    def delete_item(self,section,key):
        self.cfg.remove_option(section,key)
    def delete_section(self,section):
        self.cfg.remove_section(section)
    def add_section(self,section):
        self.cfg.add_section(section)
    def set_item(self,section,key,value):
        self.cfg.set(section,key,value)
    def save(self):
        fp=open(self.logfile,'w')
        self.cfg.write(fp)
        fp.close()
if __name__=='__main__':
    info=student_info('imooc.txt')
    info.cfg_load()
    info.cfg_dump()
    info.set_item('user info','pwd','abc')
    info.cfg_dump()
    info.add_section('login')
    info.set_item('login','2015-0511','20')
    info.cfg_dump()
    info.save()