public function getAllProductsRecursive(Category $category): Collection 	{ 		$all_products = $category->products;  		if ($category->children->isNotEmpty()) { 			$category->children()->each(function ($child) use (&$all_products) { 				$all_products = $all_products->merge($this->getAllProductsRecursive($child)); 			}); 		}  		return $all_products; 	}