The impoliteness of overriding methods(journal.stuffwithstuff.com)

  (defclass game-object ()
    ((x :accessor x :initarg :x :initform 0)
     (y :accessor y :initarg :y :initform 0)))
  
  (defmethod set-transform (renderer x y)
    ;; set the renderer coordinates here.
    )
  
  (defmethod draw-image (renderer image)
    ;; draw image here
    )
  
  (defgeneric render (game-object renderer)
    (:documentation "Render GAME-OBJECT to display using RENDERER."))
  
  
  (defmethod render :before (game-object renderer)
    (set-transform renderer (x game-object) (y game-object)))
  
  (defmethod render (game-object renderer)
    (draw-image renderer game-object))
  
  ;; Class where the :before base class method just runs
  (defclass scary-monster (game-object)
    ((image :accessor image :initarg :image)))
  
  (defmethod render ((game-object scary-monster) renderer)
    (draw-image renderer (image game-object)))
  
  ;; Class where the :before base class method is prevented from running
  ;; to prevent some undesirable action.
  (defclass happy-monster (game-object)
    ((image :accessor image :initarg :image)))
  
  (defmethod render :around ((game-object happy-monster) renderer)
    (draw-image renderer (image game-object)))
  
  ;; REPL session with the RENDER, SET-TRANSFORM and DRAW-IMAGE methods traced
  CL-USER> (render (make-instance 'scary-monster :x 1 :y 2 :image 'a) nil)
    0: (RENDER #<SCARY-MONSTER {2456D3F1}> NIL)
      1: (SET-TRANSFORM NIL 1 2)
      1: SET-TRANSFORM returned NIL
      1: (DRAW-IMAGE NIL A)
      1: DRAW-IMAGE returned NIL
    0: RENDER returned NIL
  NIL
  
  CL-USER> (render (make-instance 'happy-monster :x 3 :y 4 :image 'b) nil)
    0: (RENDER #<HAPPY-MONSTER {246A1689}> NIL)
      1: (DRAW-IMAGE NIL B)
      1: DRAW-IMAGE returned NIL
    0: RENDER returned NIL
  NIL

  package GameObject {
      use Moose;
      has ['x', 'y'] => (is => 'rw', isa => 'Num');

      sub render {
          my ($self, $renderer) = @_;
          $renderer->set_transform( $self->x, $self->y );
          inner;
      }
  }
  
  package ScaryMonster {
      use Moose;
      extends 'GameObject';
  
      augment render => sub {
          my ($self, $renderer) = @_;
          $renderer->draw_image(Images->scary_monster);
      };
  }

    var account = {
      balance: undefined,
      deposit: function(amount) {
        return balance += amount;
      }...
    }