public function setDomQuery($userid, $userkey, $action)
    {
        $request = $this->appendChild($this->createElement('query'));

        // add action, userid and userkey params
        $userid = $this->createElement('userid', $userid);
        $userkey = $this->createElement('userkey', $userkey);
        $action = $this->createElement('action', $action);

        $request->appendChild($userid);
        $request->appendChild($userkey);
        $request->appendChild($action);

        return $request;
    }