webpy session 判断登陆示例，报错attributeError: 'ThreadedDict' object has no attribute

#报错原因 ：缺少web.config.debug = False 这一句。


import web
web.config.debug = False
urls=('/login','Login',
'/logout','Logout',
)


#app=web.application(urls, locals());


#if __name__ == '__main__':
#     app.run()


t_globals = {
 'datestr': web.datestr,
 'cookie': web.cookies,
}

render = web.template.render('templates',base='base',globals=t_globals)
login_form=web.form.Form(web.form.Textbox('username',description='username'),
        web.form.Textbox('password',description='password'),
        web.form.Button("submit", type="submit", description="submit")
)

#session = web.session.Session(app, web.session.DiskStore('sessions'),initializer={'login':0,})
#session = web.session.Session(app, web.session.DiskStore('sessions'),initializer={'username': ''})

app=web.application(urls, locals());
session = web.session.Session(app, web.session.DiskStore('sessions'),)
#session.login=2

class Login:
        def GET(self):
                if logged():
                        return 'you are logged'
                else:
                        return login_form().render()
        def POST(self):
                #return 'ok'
                postdata=web.input()
                if postdata.username=='admin' and postdata.password=='admin':
                        session.login=1
                return session.login



                #return 'login'

class Logout:
        def GET(self):
                return 'logout'



def logged():
    if session.login==1:
        return True
    else:
        return False

if __name__ == '__main__':
     app.run()