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 item is immutable, and if you mutated it set up you could possibly not specialise it inside a subclass. financial benefit, worth - the amount (of money or goods or products and services) that is thought to be a fair equivalent for another thing; https://propertynewgurgaon.code.blog/