[Twisted-web] guard in web2?

Hello, is there a guard functionality in web2 that could obsolete the nevow guard? Is it under a different name perhaps? I think the guard could very well belong to web2 the same way vhost does. Or should I rewrite the guard in my code? Comments welcome, thanks! PS. if my code will be broken anyway by the obsolescence of formless and web2, to be safer in terms of API stability for the long term future, I'm considering moving away from divmod products and stick with twisted only that has a bigger chance to be solid, but the guard is something I'd rather not want to duplicate in my code given it may be useful to more people like vhost.