知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。 @MarkusMeskanen: as the object is immutable, and if you mutated it in place you could possibly not specialise it inside a subclass. One more factor chances are you'll consider, if you are not able to change the original form, is extending the sort like so: From time https://lowriseprojectingurgaon.blogspot.com/