diff --git a/src/misc/batch_rename.py b/src/misc/batch_rename.py
index 790abd7..cdc5c0b 100644
--- a/src/misc/batch_rename.py
+++ b/src/misc/batch_rename.py
@@ -7,7 +7,7 @@ import re
 
 import logging
 
-logging.basicConfig(level=logging.DEBUG, 
+logging.basicConfig(level=logging.DEBUG,
                     format='%(asctime)s.%(msecs)03d %(levelname)-8s %(message)s',
                     datefmt='%H:%M:%S')
 
@@ -26,10 +26,11 @@ class Error(Exception):
 # Star.Trek.The.Next.Generation.1x01-02.Encounter.At.Farpoint.DVDRip-AMC.[tvu.org.ru].avi
 # Star Trek TNG - 1x01-2 - Encounter At Farpoint - DVDRip-AMC.divx.avi
 
-def main(argv = None):
-    if argv == None:
+
+def main(argv=None):
+    if argv is None:
         argv = sys.argv
-    LOG.info("starting [%s]" % (argv[0],)) 
+    LOG.info("starting [%s]" % (argv[0],))
     try:
         try:
             opts, args = getopt.getopt(argv[1:], "h", ["help"])
@@ -38,11 +39,11 @@ def main(argv = None):
             raise Usage(msg)
         # more code, unchanged
         # p = re.compile("Star\.Trek\.The\.Next\.Generation.(.*?)\.(.*)\.(DVDRip-.*)\.\[tvu.org.ru\]\.avi")
-        p = re.compile("Shaun\.The\.Sheep\..*\.(.*)\.DVDRip\.XviD-WPi\.\[tvu\.org\.ru\]\.avi")        
+        p = re.compile("Shaun\.The\.Sheep\..*\.(.*)\.DVDRip\.XviD-WPi\.\[tvu\.org\.ru\]\.avi")
         # tng = r"c:\Dokumente\Eigene Videos\Shaun the Sheep"
         tng = "."
         # os.chdir(tng)
-        for (dirpath, dirnames, filenames) in os.walk(tng):
+        for (_, _, filenames) in os.walk(tng):
             for f in filenames:
                 mot = re.match(p, f)
                 if mot is not None:
@@ -51,8 +52,8 @@ def main(argv = None):
                     title1 = title0.replace('.', ' ')
                     nf = r"%s - DVDRip [tvu.org.ru].avi" % (title1,)
                     # os.rename(f, nf)
-                    print 'ren "%s" "%s"' % (f, nf) 
-                    
+                    print 'ren "%s" "%s"' % (f, nf)
+
     except Error, err:
         LOG.error(err.message)
         return 1
diff --git a/src/zodb/tutorial.py b/src/zodb/tutorial.py
index fbeb21f..2f36646 100644
--- a/src/zodb/tutorial.py
+++ b/src/zodb/tutorial.py
@@ -1,9 +1,14 @@
-#! /usr/bin/env python2
+#!/usr/bin/env python
 # -*- coding: cp1252 -*-
+# Copyright (c) 2014 Andreas
+# See LICENSE for details.
 
-# ZODB Tutorial
+""" tutorial """
 
-""" zodb.tutorial """
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
 
 # imports
 
@@ -14,6 +19,7 @@ import transaction
 
 # Persistent objects
 
+
 class Account(Persistent):
     def __init__(self):
         self.balance = 0.0
@@ -27,29 +33,35 @@ class Account(Persistent):
 
 # Configuration
 
-storage = FileStorage(r"e:\workspaces\zodb3\data.zodb")
+storage = FileStorage(r"e:\workspaces\zodb3\tutorial.zodb")
 db = DB(storage)
-connection = db.open()
-root = connection.root()
+ctx = db.open()
+root = ctx.root()
 
-print root.keys()
+print(root.keys())
 
 # Storing objects
-    
-root['account-1'] = Account()
-if "account-2" not in root: 
-    root['account-2'] = Account()
 
+a = b = Account()
+
+root['account-1'] = a
+if "account-2" not in root:
+    root['account-2'] = b
+
+print("id(a): {}, id(b): {}".format(id(a), id(b)))
 # Transactions
 root['account-2'].deposit(5)
 transaction.commit()
-print root.keys()
+print(root.keys())
 
 del root['account-1']
-print root.keys()
+print(root.keys())
 # ['account-2']
 transaction.abort()
-print root.keys()
+print(root.keys())
 # ['account-1', 'account-2']
 
-print root['account-2'].balance 
\ No newline at end of file
+print(root['account-2'].balance)
+a = root['account-1']
+b = root['account-2']
+print("id(a): {}, id(b): {}".format(id(a), id(b)))