title: Check if user is disabled in an appengine application using openid
body: <p>I have an application written in Google App Engine (Python 2.7) where users can authenticate using OpenID. I would like to have the ability to disable access to some of those users, according to a field <code>disabled</code> which I have on a <code>UserProfile</code> table.</p>
  
  <p>Is it possible to add a step to the OpenID authentication so that after the round trip to the OpenID provider the user is checked to be active before forwarding it to the value of the <code>continue</code> parameter? Or is there another workaround?</p>