根据数据范围更改链路.基本错误，我找不到，我试图回显情况10

<?php
$next_month = strtotime("+1 month");
//
$next_month_formatted = date("n", $next_month);
$link = "";
if(! empty($next_month_formatted))
    switch($next_month_formatted % 5)
    {
        case '10':
            $link = "https://rightsignature.com/forms/10-1-15-MCDONALDS-e13aff/token/da0d4ec67cf";
        break;
        case '11':
            $link = "https://rightsignature.com/forms/11-1-15-MCDONALDS-a0a0ec/token/8232d7c2265";
        break;
        case '12':
            $link = "https://rightsignature.com/forms/121-15-MCDONALDS--89d5a0/token/84b88a8c248";
        break;
        case '1':
            $link = "https://rightsignature.com/forms/1-1-16-MCDONALDS--fa49d9/token/79dd025e3f1q";
        break;
        case '2':
            $link = "https://rightsignature.com/forms/2-1-16-MCDONALDS--022aff/token/4bc0a37cf49";
        break;
        case '3':
            $link = "https://rightsignature.com/forms/3-1-16-MCDONALDS--d1313d/token/47b351070c1";
        break;
        case '4':
            $link = "https://rightsignature.com/forms/4-1-16-MCDONALDS--0cf9d2/token/bb31f6bb11e";
        break;
        case '5':
            $link = "https://rightsignature.com/forms/5-1-16-MCDONALDS--37e75d/token/d1b044125f2";
        break;
        default:
            $link = "#";
    }
    echo $next_month_formatted(10);
?>

我试图获得返回值，但我有一个错误的函数。我是新来的，所以我不能准确地描述它是什么。我正在根据数据范围更改日期。

我正在尝试回显当前月份。我试图反映十月的链接，这是案例10。