public function capabilities($path, $token = null)
    {
        $params = [
            'body' => json_encode(array_filter(compact('token', 'path')))
        ];

        if (empty($token)) {
            return $this->client->post('/v1/sys/capabilities-self', $params);
        }

        return $this->client->post('/v1/sys/capabilities', $params);
    }