diff --git a/pysrt/srtitem.py b/pysrt/srtitem.py
index 5597905..55a15ca 100644
--- a/pysrt/srtitem.py
+++ b/pysrt/srtitem.py
@@ -58,7 +58,7 @@ def __str__(self):
         __unicode__ = __str__
 
         def __str__(self):
-            raise NotImplementedError('Use unicode() instead!')
+            raise NotImplementedError('Use unicode() instead for python 2!')
 
     def _cmpkey(self):
         return (self.start, self.end)