diff --git a/Final/1.rkt b/Final/1.rkt
index d0b89f7..11c768b 100644
--- a/Final/1.rkt
+++ b/Final/1.rkt
@@ -32,7 +32,14 @@
      (interp bound-body (extend env bound-id (interp named-expr env)))]
     [(varE name) (lookup name env)]
     [(lamE bound-id bound-body) (lamV bound-id bound-body env)]
-    [(callWith with-id with-expr fun-expr arg-expr) ....]
+    ; Wordy double extend, as first setting up the f-env with the value it is dynamically scoped with.
+    ; Then, extending that environment with the function that is being used on the value.
+    [(callWith with-id with-expr fun-expr arg-expr)
+     (let ([fval (interp fun-expr env)])
+       (type-case Value fval
+         [(lamV bound-id bound-body f-env)
+          (interp bound-body (extend (extend f-env with-id (interp with-expr env)) bound-id (interp arg-expr env)))]
+         [else (error 'interp "non-function")]))]
     [(appE fun-expr arg-expr)
      (let ([fval (interp fun-expr env)])
        (type-case Value fval