添加参数的函数不起作用

我对下面的代码有疑问。

当我使用带有如下参数的函数时 sum_warehouses_stock("CALL", "2", "B", "10", "CALL", 1 ) ,它返回零而不是数字相加。我忽略了什么吗?

function sum_warehouses_stock(){

    $total = 0;
    $warehouses = func_get_args();

    foreach($warehouses as $warehouse){
    $warehouse = str_replace(["+","<",">","B"], "", $warehouse);
        if (is_numeric($warehouse)){
             $total += $warehouse;
        }
     }
     return $total;
}