diff --git a/README.org b/README.org
index 25d082f..c626a58 100644
--- a/README.org
+++ b/README.org
@@ -4933,7 +4933,7 @@ Listing [[lst:bug-reference-mode]] configures ~bug-reference-mode~ for use with
 (defvar bug-reference-url-format
   "https://debbugs.gnu.org/cgi/bugreport.cgi?bug=%s"
   "Format to use `gnu-debbugs' URL.")
-(put 'bug-reference-mode 'safe-local-variable 'booleanp))
+(put 'bug-reference-mode 'safe-local-variable 'booleanp)
 #+end_src
 
 *** [[info:elisp#Debugging][Debugging Emacs Lisp (info)]]