diff --git a/Lib/cookielib.py b/Lib/cookielib.py
index 65214df..f9c8d2f 100644
--- a/Lib/cookielib.py
+++ b/Lib/cookielib.py
@@ -1,4 +1,4 @@
-"""HTTP cookie handling for web clients.
+r"""HTTP cookie handling for web clients.
 
 This module has (now fairly distant) origins in Gisle Aas' Perl module
 HTTP::Cookies, from the libwww-perl library.