public function addPingback($url)
    {
        $response = $this
            ->getHttpClient()
            ->request('GET', "/res.php?key={$this->apiKey}&action=add_pingback&addr={$url}");

        $responseText = $response->getBody()->__toString();

        if ($responseText === self::STATUS_OK) {
            return true;
        }

        throw new ErrorResponseException(
            $this->getErrorMessage($responseText) ?: $responseText,
            $this->getErrorCode($responseText) ?: 0
        );
    }