Рекрусивная функция в Битрикс, php [требует правки]

<?if (!defined("B_PROLOG_INCLUDED") || B_PROLOG_INCLUDED!==true)die(); 
 
if (!empty($arResult)) { 
foreach($arResult as $arItem) { 
	switch($arItem['DEPTH_LEVEL']) { 
		case 1: 
			$key_1++; 
			$arResult_new[$key_1]=$arItem; 
		break; 
		case 2: 
			$key_2++; 
			$arResult_new[$key_1]['CHILDRENS'][$key_2]=$arItem; 
		break; 
		case 3: 
			$key_3++; 
			$arResult_new[$key_1]['CHILDRENS'][$key_2]['CHILDRENS'][$key_3]=$arItem; 
		break; 
		case 4: 
			$key_4++; 
			$arResult_new[$key_1]['CHILDRENS'][$key_2]['CHILDRENS'][$key_3]['CHILDRENS'][$key_4]=$arItem; 
		break; 
	} 
} 
$arResult=$arResult_new; 
}