一个类只继承自一个相关的有效性类型，然后通过添加类属性进行专门化(如果需要的话)。

A class simply inherits from a relevant validity type, and then specializes (if necessary) by adding a class attribute.

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然而，对齐属性的有效性将受到固有的连接器局限性的限制。

The effectiveness of aligned attributes, however, is limited by inherent linker limitations.

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Quantification的具体子类必须添加_ type类属性，它简单地指向另一个有效性类。

A concrete descendent of Quantification must add a _type class attribute, which simply points to another validity class.

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