The self keyword points to the containing class and is unaware of subclasses.

self关键字指向的是包含类，且不会意识到子类。

youdao

As with properties, any attempt to call a private method from outside the containing class causes a fatal error.

与属性一样，尝试从包含类外部调用私有方法将导致致命错误。

youdao

Implement the extension method as a static method with at least the same visibility as the containing class.

以至少与包含类别相同的可视性，将扩充方法实作为静态方法。

youdao

Treseder has come from coaching a team containing three world-class centres.

BBC: SPORT | Other Sport... | Disability Sport | Treseder heralds new era

They are widely regarded as a world-class natural attraction containing marvellous stream passages formed by three rivers that sink underground on the slopes of Cuilcagh Mountain.

UNESCO: Olympic torch carried through iconic Geopark

Alongside these new films, Sky Movies customers will also have exclusive access to Entertainment Film Distributors' world-class back catalogue containing a wide range of classic titles including Brokeback Mountain, The Departed, Gangs of New York, American Psycho and Ali.

ENGADGET: Sky Movies lands deal with Entertainment Film Distributors to stream top movies