diff --git a/gnu/home/services/sway.scm b/gnu/home/services/sway.scm
index fcddbdbea2..e9a488f1ca 100644
--- a/gnu/home/services/sway.scm
+++ b/gnu/home/services/sway.scm
@@ -104,7 +104,8 @@
 
 ;; Helper function.
 (define (flatmap f l)
-  (let loop ((lst (reverse l)) (acc '()))
+  (let loop ((lst (reverse l))
+             (acc '()))
     (match lst
       (() acc)
       ((head . tail)