Update step_4.rkt

step_4.rkt

@@ -16,6 +16,8 @@
 ; of our inheritance hierarchy.
 ; Thus, in this case, we do not propagate the set_self! method and instead only dynamically bind the local self_ref value.
 (define (object)
+  ; Since object is the root of the hierarchy, it has no super value, here represented as a 'nil value.
+  (define super 'nil)
   ; #f is the default value before any binding
   (define self_ref #f)
   (define (set-self! ref) (set! self_ref ref))
@@ -99,10 +101,10 @@
 ; It will then create the new object, and initiate the dynamic binding of self through
 ; a 'set-self call.
 (define (new object-class . class-args)
-  (let ((temp (apply object-class class-args)))
+  (let ((new_object (apply object-class class-args)))
     (begin
-      (send temp 'set-self! temp)
-      temp
+      (send new_object 'set-self! new_object)
+      new_object
       )
     )
   )