如果某个接口与该绑定相关联，binding可以选择声明一个子operation元素，用于镜像接口的operation元素。

If an interface is associated with the binding, the binding element can optionally declare a child operation element that mirrors the interface operation element.

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然而，消费者所提供接口和所需接口的含义与提供者所提供接口和所需接口的含义是镜像关系。

However, the sense of the provided and the required interfaces for the consumer is the mirror image of the sense of the provided and the required interfaces for the provider.

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