diff --git a/tools/system_messages.py b/tools/system_messages.py
index 3ef3aa3478..6cf3ce9411 100644
--- a/tools/system_messages.py
+++ b/tools/system_messages.py
@@ -138,8 +138,7 @@ SEC_SEPARATOR = ""
 SEC_TRAILER = """      </variablelist>
     </para>
   </chapter>
-</book>
-"""
+</book>"""
 
 
 def reportError(filename, what):