(define (partition pivot num-list)
    (cond ((null? num-list) '(() ()))
          ((< pivot (car num-list))
            (list (cons (car num-list) (car (partition pivot (cdr num-list))))
                  (cadr (partition pivot (cdr num-list)))))
          (else list (car (partition pivot (cdr num-list)))
                     (cons (car num-list) (cadr (partition pivot (cdr num-list)))))))