Problem 3: No Repeats (100 pts)

Implement no-repeats, which takes a list of numbers s as input and returns a list that has all of the unique elements of s in the order that they first appear, but no repeats. For example, (no-repeats (list 5 4 5 4 2 2)) evaluates to (5 4 2).

Hints: To test if two numbers are equal, use the = procedure. To test if two numbers are not equal, use the not procedure in combination with =. You may find it helpful to use the filter-lst procedure.

(define (no-repeats s)
  'YOUR-CODE-HERE
)

;;; Tests
; scm> (no-repeats (list 5 4 5 4 2 2))
; (5 4 2)