private function migrateSize(?string $size): ?string
    {
        if ($size === null) {
            return null;
        }


        $columns = array_map(
            function (array $column) {
                if ($column['width'] === 'auto') {
                    $column['width'] = 'equal';
                }

                return $column;
            },
            StringUtil::deserialize($size, true)
        );

        return serialize($columns);
    }