public function deleteWatermark($watermarkId, $options = array())
    {
        list($config) = $this->parseOptions($options, 'config');
        if (empty($watermarkId)) {
            throw new BceClientException("The parameter watermarkId "
                ."should NOT be null or empty string");
        }
        return $this->sendRequest(
            HttpMethod::DELETE,
            array(
                'config' => $config,
            ),
            "/watermark/$watermarkId"
        );
    }