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(define (make-object name) (list 'name name))
(define object->name cadr)

(define names (list "john" "paul" "george" "ringo"))
(define objects (map make-object names))

(define (contains? objects names)
  (define (names-contains? name)
    (let loop ((names names))
      (cond
       ((null? names) #f)
       ((string=? name (car names)) #t)
       (else (loop (cdr names))))))
  (let loop ((object-names (map object->name objects)))
    (cond
     ((null? object-names)
      #t)
     ((not (names-contains? (car object-names)))
      #f)
     (else (loop (cdr object-names))))))

(define (p message result)
  (display message)
  (display result)
  (newline))

(p "This test passed: " (contains? objects names))
(p "This test passed: " (not (contains? (cons (make-object "duncan") objects) names)))