diff --git a/pdfrw/objects/pdfstring.py b/pdfrw/objects/pdfstring.py
index d6b2db0..a2aac7c 100644
--- a/pdfrw/objects/pdfstring.py
+++ b/pdfrw/objects/pdfstring.py
@@ -3,7 +3,7 @@
 #                    2016 James Laird-Wah, Sydney, Australia
 # MIT license -- See LICENSE.txt for details
 
-"""
+r"""
 
 ================================
 PdfString encoding and decoding
@@ -404,7 +404,7 @@ def init_unescapes(cls):
         return unescape_func
 
     def decode_literal(self):
-        """Decode a PDF literal string, which is enclosed in parentheses ()
+        r"""Decode a PDF literal string, which is enclosed in parentheses ()
 
         Many pdfrw users never decode strings, so defer creating
         data structures to do so until the first string is decoded.