在Swift4.0中我可以这样写protocolObserversHolder{///CompilingErrorinSwift4.1///note:possiblyintendedmatch'StringManager.ObserverValue'(aka'StringObserver')doesnotconformto'AnyObject'///note:protocolrequiresnestedtype'ObserverValue';doyouwanttoaddit?associatedtypeObserverValue:AnyObjectvarobservers:[Obser