The class argument is a CLOS class, or the name of a CLOS class, which shadows a Loom concept.
(setq ?i (make-object 'Single)) ==> \#<Single \#X20FA286> (retrieve ?x (Single ?x)) ==> (\#<Single \#X20FA286>) (change-object ?i 'Married) ==> (\#<Married \#X20FA286>) (retrieve ?x (Single ?x)) ==> NIL (retrieve ?x (Married ?x)) ==> (\#<Married\ \#X20FA286>) (change-object ?i (find-class 'Single)) ==> (\#<Single \#X20FA286>) (ask (Single ?i)) ==> T