title: Racket what does the procedure
body: <p>I have a procedure but actually I don't know what it does.
  Will anybody explain it?</p>
  
  <pre><code>(define (stj fun listt)
    (if (null? listt)
        `()
        (cons (fun (car listt)) (stj fun (cdr listt)))))
  </code></pre>