AlternativeObjectProxy class-instance creation - GNU Smalltalk Library Reference

acceptUsageForClass: aClass: The receiver was asked to be used as a proxy for the class aClass. Answer whether the registration is fine. By default, answer true except if AlternativeObjectProxy itself is being used.
on: anObject: Answer a proxy to be used to save anObject. IMPORTANT: this method MUST be overridden so that the overridden version sends #on: to super passing an object that is NOT the same as anObject (alternatively, you can override #dumpTo:, which is what NullProxy does), because that would result in an infinite loop! This also means that AlternativeObjectProxy must never be used directly – only as a superclass.