public function create($category, $attribute, $value, $parent = null) {
        $params = [
            'category' => $category,
            'property' => $attribute,
            'value' => $value
        ];

        if (isset($parent)) {
            $params['parent'] = $parent;
        }

        $result = $this->api->request(
            'cmdb.dialog.create',
            $params
        );

        if (!array_key_exists('entry_id', $result) ||
            !is_numeric($result['entry_id'])) {
            throw new RuntimeException('Bad result');
        }

        return (int) $result['entry_id'];
    }