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 webweb.config.debug = Falseurls=('/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=2class 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 Falseif __name__ == '__main__':     app.run()