Problem 5: Sub All (100 pts)

Write sub-all, which takes a list s, a list of old words, and a list of new words; the last two lists must be the same length. It returns a list with the elements of s, but with each word that occurs in the second argument replaced by the corresponding word of the third argument. You may use substitute in your solution. Assume that olds and news have no elements in common.

(define (sub-all s olds news)
  'YOUR-CODE-HERE
)

;;; Tests
; scm> (sub-all '(a (a b c) d) '(b d) '(e f))
; (a (a e c) f)