diff --git a/__init__.py b/__init__.py
index f3f8fb8931..c9e6c5cbe3 100644
--- a/__init__.py
+++ b/__init__.py
@@ -1,5 +1,5 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 
 from trytond.pool import Pool
 from .sale import *
diff --git a/product.py b/product.py
index 14dd0376ca..61a889650e 100644
--- a/product.py
+++ b/product.py
@@ -1,5 +1,5 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 from trytond.model import fields
 from trytond.pool import PoolMeta
 from trytond.pyson import Eval
diff --git a/purchase.py b/purchase.py
index 82283285db..5abadbadcf 100644
--- a/purchase.py
+++ b/purchase.py
@@ -1,5 +1,5 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 from itertools import chain
 
 from trytond.model import ModelView, Workflow
diff --git a/sale.py b/sale.py
index ea763ff8bf..be8b629ed2 100644
--- a/sale.py
+++ b/sale.py
@@ -1,8 +1,7 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 from trytond.model import fields
 from trytond.pool import Pool, PoolMeta
-from trytond.transaction import Transaction
 from trytond.pyson import Eval
 
 __all__ = ['Sale', 'SaleLine']
diff --git a/setup.py b/setup.py
index 8a9a6fde82..9bb2d87170 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 
 from setuptools import setup
 import re
diff --git a/stock.py b/stock.py
index dc1f8eb2e2..3739cc4dc2 100644
--- a/stock.py
+++ b/stock.py
@@ -1,8 +1,7 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 from trytond.model import ModelView, Workflow
 from trytond.pool import Pool, PoolMeta
-from trytond.transaction import Transaction
 
 
 __all__ = ['ShipmentIn']
diff --git a/tests/__init__.py b/tests/__init__.py
index 81becbbe47..e80754c52d 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1,5 +1,5 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 
 from test_sale_supply import suite
 
diff --git a/tests/test_sale_supply.py b/tests/test_sale_supply.py
index 66164f4818..8837400727 100644
--- a/tests/test_sale_supply.py
+++ b/tests/test_sale_supply.py
@@ -1,5 +1,5 @@
-#This file is part of Tryton.  The COPYRIGHT file at the top level of
-#this repository contains the full copyright notices and license terms.
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
 import unittest
 import doctest
 import trytond.tests.test_tryton