如何在symfony 1.4中创建/使用自定义类和帮助器？

// lib/my_classes/MyCustomClass.php

class MyCustomClass
{
    public function myMethod()
    {
        // 实现自定义方法
    }
}

// apps/[app_name]/modules/[module_name]/lib/helper/MyCustomHelper.php

class MyCustomHelper extends sfHelper
{
    public function myMethod()
    {
        // 实现自定义方法
    }
}

<?php use my_classes\MyCustomClass; ?>
<?php use apps\[app_name]\modules\[module_name]\lib\helper\MyCustomHelper; ?>

<?php $myCustomClass = new MyCustomClass(); ?>
<?php echo $myCustomClass->myMethod(); ?>

<?php $myCustomHelper = new MyCustomHelper(); ?>
<?php echo $myCustomHelper->myMethod(); ?>

use my_classes\MyCustomClass;
use apps\[app_name]\modules\[module_name]\lib\helper\MyCustomHelper;

$myCustomClass = new MyCustomClass();
$result = $myCustomClass->myMethod();

$myCustomHelper = new MyCustomHelper();
$result = $myCustomHelper->myMethod();