@classmethod
def validated_user(cls, req):
    """login validation is now handled by Twisted.cred.  If we have got this far
       then the password has been successfully checked and the users id is
       available as req.request.avatarId
    """
    user = cls.Session.fetch_user(req)
    if user.uid > 1 and req.get('evokeLogin'):
        forever = 10 * 365 * 24 * 3600
        if req.get('evokePersist'):
            req.set_cookie('evokePersist', user.id, expires=forever)
        elif req.cookies.get('evokePersist') == user.id:
            req.clear_cookie('evokePersist')
    return user
