(define (new-instance class . parameters)
  (apply class parameters))

(define (new-part class . parameters)
  (apply class parameters))

(define (method-lookup object selector)
 (cond ((procedure? object) (object selector))
       (else
         (error "Inappropriate object in method-lookup: "
                 object))))

(define (send message object . args)
 (let ((method (method-lookup object message)))
  (cond ((procedure? method) (apply method args))
        ((null? method)
         (error "Message not understood: " message))
        (else 
         (error "Inappropriate result of method lookup: "
                 method)))))