koa下的koa-session-mongoose和koa-session-mongo的超时时间为毛线都无效？

var session = require('koa-session-store'),
    mongoose = require('mongoose'),
    mongooseStore = require('koa-session-mongoose');
    
mongoose.connect('mongodb://igwo:igwo321321[@127](/user/127).0.0.1:27017/igwo');

app.use(session({
    store: mongooseStore.create({
        expires: 1000*5
    })
}));

可以保存session，但是超时时间不对啊T-T