diff --git a/window-numbering.el b/window-numbering.el
index 4c89e9c..00650d1 100644
--- a/window-numbering.el
+++ b/window-numbering.el
@@ -162,12 +162,12 @@ windows to numbers."
   (let ((windows (window-list nil 0 (frame-first-window))))
     (run-hook-with-args 'window-numbering-before-hook windows)
     (when window-numbering-assign-func
-      (mapc `(lambda (window)
-               (with-selected-window window
-                 (with-current-buffer (window-buffer window)
-                   (let ((num (funcall ,window-numbering-assign-func)))
-                     (when num
-                       (window-numbering-assign window num))))))
+      (mapc (lambda (window)
+              (with-selected-window window
+                (with-current-buffer (window-buffer window)
+                  (let ((num (funcall window-numbering-assign-func)))
+                    (when num
+                      (window-numbering-assign window num))))))
             windows))
     (dolist (window windows)
       (window-numbering-assign window))))