diff --git a/Tools/msi/msilib.py b/Tools/msi/msilib.py
index 4595246880c..5f8ef28ab6b 100644
--- a/Tools/msi/msilib.py
+++ b/Tools/msi/msilib.py
@@ -7,6 +7,11 @@ import pythoncom, pywintypes
 from win32com.client import constants
 import re, string, os, sets, glob, popen2, sys, _winreg
 
+try:
+    basestring
+except NameError:
+    basestring = (str, unicode)
+
 Win64 = 0
 
 # Partially taken from Wine