diff --git a/kitty/config.py b/kitty/config.py
index 922ab8d4a..3c629b258 100644
--- a/kitty/config.py
+++ b/kitty/config.py
@@ -206,6 +206,7 @@ def to_layout_names(raw):
     for p in parts:
         if p not in all_layouts:
             raise ValueError('The window layout {} is unknown'.format(p))
+    return parts
 
 
 def positive_int(x):