Fix most flake8 errors

review8771002

__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 .party import *

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.pool import PoolMeta
-from trytond.transaction import Transaction
 
 __metaclass__ = PoolMeta
 __all__ = ['Sale']

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

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_shipment_grouping import suite
 

tests/test_sale_shipment_grouping.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