function setAllowedTypes($allowed_types)
    {
        foreach ($allowed_types as $pair) {
            list($assoc_type, $session_type) = $pair;
            if (!Auth_OpenID_checkSessionType($assoc_type, $session_type)) {
                return false;
            }
        }

        $this->allowed_types = $allowed_types;
        return true;
    }