Once the instance is constructed, you can call the invoice and manifest functions on your PurchaseOrder object, which uses the implementations provided in the defrecord.

一旦构造了实例，您就可以在您的 PurchaseOrder 对象上调用 invoice 和 manifest 函数，其使用在 defrecord 中提供的实现。

youdao

I've cut out all of the HTML markup code here for brevity; you can see it in the Invoice.

为了简单明了我已经删掉了此处所有的 HTML 标记代码；

youdao

And with that, you have polymorphic invoice and manifest functions that can be called on either an Order or a Contract and that will do the right thing.

就这样，您具有多态invoice和manifest函数，可以在一个Order或一个Contract上调用且作出正确操作。

youdao

You can, for instance, attach a billing invoice to a payment.

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