public function find($graphId)
    {
        $this->login();

        return $this->httpClient->get('chart2.php', [
            'query' => [
                'graphid' => $graphId,
                'width' => $this->width,
                'height' => $this->height,
                'stime' => $this->startTime->getTimestamp(),
                'period' => $this->endTime->getTimestamp() - $this->startTime->getTimestamp(),
            ],
        ])->getBody()->getContents();
    }