diff --git a/pkgs/htdp-pkgs/htdp-lib/2htdp/private/img-err.rkt b/pkgs/htdp-pkgs/htdp-lib/2htdp/private/img-err.rkt
index 76d94a4d9c..ca62354b75 100644
--- a/pkgs/htdp-pkgs/htdp-lib/2htdp/private/img-err.rkt
+++ b/pkgs/htdp-pkgs/htdp-lib/2htdp/private/img-err.rkt
@@ -229,7 +229,9 @@
      (check-arg fn-name (or (not arg) (string? arg)) 'face i arg)
      arg]
     [(family)
-     (check-arg fn-name (memq arg '(default decorative roman script swiss modern symbol system)) 'family i arg)
+     (check-arg fn-name
+                (memq arg '(default decorative roman script swiss modern symbol system))
+                'family i arg)
      arg]
     [(style)
      (check-arg fn-name (memq arg '(normal italic slant)) 'style i arg)