public function setStatus($sStatus)
    {
        if (!$this->bIsLocked) {

            $aStatuses = $this->getStatuses();
            if (!in_array($sStatus, $aStatuses)) {
                throw new ResponseException('"' . $sStatus . '" is an invalid response status.', 1);
            }

            $this->sStatus = $sStatus;
        }

        return $this;
    }