# How do I extend pipelines?

The payload data can be altered using the `extend()` method. This is typically done from within a Service Provider:

- If the code is unique to a particular store it could be placed in the `boot()` method of the `AppServiceProvider`.
- If it is to be included as part of a module, then it can be added to the setup method of the module's Service Provider.

For example, if a module needs to add an option to items to flag them as requiring gift wrap, the `CartItemBuilder` pipeline class should be extended in the module's ServiceProvider as shown below:

```php
<?php

namespace Aerocargo\Acme;

use Aero\Cart\CartItemOption;
use Aero\Common\Providers\ModuleServiceProvider;
use Aero\Store\Pipelines\CartItemBuilder;

class ServiceProvider extends ModuleServiceProvider
{
    public function setup() 
    {
        CartItemBuilder::extend(function ($item) {
            if (request()->has('gift_wrap')) {
                $option = CartItemOption::create('Gift wrap');

                $item->addOption($option);
            }
        });
    }
}
```