Patch# 1258 by Christian Heimes: kill basestring.
I like this because it makes the code shorter! :-)
diff --git a/Lib/fileinput.py b/Lib/fileinput.py
index 5a423a1..0d7ffad 100644
--- a/Lib/fileinput.py
+++ b/Lib/fileinput.py
@@ -196,7 +196,7 @@
 
     def __init__(self, files=None, inplace=0, backup="", bufsize=0,
                  mode="r", openhook=None):
-        if isinstance(files, basestring):
+        if isinstance(files, str):
             files = (files,)
         else:
             if files is None: