diff --git a/chat-sync.rkt b/chat-sync.rkt
index 0e61bdc..e098e70 100644
--- a/chat-sync.rkt
+++ b/chat-sync.rkt
@@ -50,8 +50,7 @@
      (set! active-connections new-connections))))
 
 (define (depart! connection-id)
-  (call-with-semaphore
-   active-connection-mutex
+  (call-with-semaphore active-connection-mutex
    (lambda ()
      (define new-connections (set-remove active-connections (cons (current-thread) connection-id)))
      (set! active-connections new-connections)