diff --git a/racket/syndicate/examples/actor/file-system.rkt b/racket/syndicate/examples/actor/file-system.rkt
index 4bbb65e..3516257 100644
--- a/racket/syndicate/examples/actor/file-system.rkt
+++ b/racket/syndicate/examples/actor/file-system.rkt
@@ -8,11 +8,11 @@
 (actor (react (field [files (hash)])
               (on (asserted (observe (file $name _)))
                   (printf "At least one reader exists for ~v\n" name)
-                  (begin0 (until (retracted (observe (file name _)))
-                                 (field [content (hash-ref (files) name #f)])
-                                 (assert (file name (content)))
-                                 (on (message (save (file name $new-content))) (content new-content))
-                                 (on (message (delete name)) (content #f)))
-                    (printf "No remaining readers exist for ~v\n" name)))
-                (on (message (save (file $name $content))) (files (hash-set (files) name content)))
-                (on (message (delete $name)) (files (hash-remove (files) name)))))
+                  (until (retracted (observe (file name _)))
+                         (field [content (hash-ref (files) name #f)])
+                         (assert (file name (content)))
+                         (on (message (save (file name $new-content))) (content new-content))
+                         (on (message (delete name)) (content #f)))
+                  (printf "No remaining readers exist for ~v\n" name))
+              (on (message (save (file $name $content))) (files (hash-set (files) name content)))
+              (on (message (delete $name)) (files (hash-remove (files) name)))))