anchor.diff:  (define-test test-clos-getters-and-setters
       (let ((ship-1 (make-instance 'spaceship)))
         (set-color :orange ship-1)
  -      (assert-equal ____ (get-color ship-1))
  +      (assert-equal :orange (get-color ship-1))
         (set-speed 1000 ship-1)
  -      (assert-equal ____ (get-speed ship-1))))
  +      (assert-equal 1000 (get-speed ship-1))))
   
   ;; CLOS also provides functionality to create accessors
   ;; to object data.
  
positive.code: (define-test test-multiple-inheritance
      (let ((my-colored-circle (make-instance 'colored-circle))
            (my-circled-color (make-instance 'circled-color)))
        (assert-equal ____ (get-kind my-colored-circle))
        (assert-equal ____ (get-kind my-circled-color))))
  
  
  (defvar *last-kind-accessor* nil)
  
negative.code: (define-test test-inheritance
      (let ((circle-1 (make-instance 'circle))
            (shape-1 (make-instance 'shape)))
        (assert-equal 'shape (type-of shape-1))
        (assert-equal 'circle (type-of circle-1))
        (true-or-false? t (typep circle-1 'circle))
        (true-or-false? t (typep circle-1 'shape))
        (set-kind :circle circle-1)
        (set-pos '(3 4) circle-1)
        (set-radius 5 circle-1)
        (assert-equal '(3 4) (get-pos circle-1))
        (assert-equal 5 (get-radius circle-1))))
  
  ;; Classes may also inherit from more than one base class.
  ;; This is known as multiple inheritance.
  