Functional programming Racket博士，反对者：预期2个论点，但发现3个

我有这个函数和其他一些函数，但当我运行它时，racket博士说：

缺点：期望2个参数，但找到3个

我想不出哪里的

cons

不正确，有人能帮我吗

;; Component -> ListOfCode
;; produce a list of codes of all parts required to build the given component
;; if a part appears twice, the code of the bar should also appear twice

(check-expect (list-code C0) (cons "000000" (cons "111000" (cons "222000" empty))))
(check-expect (list-code C1) (cons "000000" (cons "111000" (cons "111000" (cons 444000 empty)))))
(check-expect (list-code C3) (cons "000000" (cons "111000" (cons "555000" (cons "666000" (cons "666000" (cons "000000" (cons "111000" (cons "222000" (cons "000000" (cons "111000" (cons "111000" (cons 444000 empty)))))))))))))

;(define (list-code c) loc)
(define (list-code c)
  (cons (find-codes-loc (component-loc c))    ;fn-for-loc
        (get-code-lop (component-lop c))  ;fn-for-lop
        empty))

在这里：

(define (list-code c)
  (cons (find-codes-loc (component-loc c))  -- argument 1
        (get-code-lop (component-lop c))    -- argument 2
        empty))                             -- argument 3