protected function getMergedLinesText(array $parent, array $children)
    {
        $childrenTexts = array();
        foreach ($children as $child) {
            $childrenTexts[] = $child[Tag::Product];
        }
        $childrenText = ' (' . implode(', ', $childrenTexts) . ')';
        return $parent[Tag::Product] .  $childrenText;
    }