(define-class
  's-stack
  stack-class
  '()
  '(multi-pop))
  
(class/set-method!
 s-stack-class 'multi-pop
 (lambda (this amount)
   (if (= amount 0)
       'done
       (begin (stack/pop this) 
              (s-stack/multi-pop this (- amount 1))))))
		   
(class/set-method! 
 s-stack-class 'display
 (lambda (this)
   (display "output from the display method of s-stack class")
   (stack^display this)))