[racket] Problems with Plot

Hi All --

I pulled this from the Docs on plot --

(require plot)

 (plot (function (λ (x) (sin (* 4 x))) -1 1)
        #:x-min -1.5 #:x-max 1.5 #:y-min -1.5 #:y-max 1.5)

-- ran it in Dr. Racket, and received the following error: "#%datum: keyword used as an expression" with "#:x-min" highlighted in pink.   I've run plot functions before and never had a problem.  Am using Racket version 5.3.6. 

What am I doing wrong? Apologies in advance if I'm making an obvious mistake. 

Thanks!
Dave