diff --git a/openerp/modules/migration.py b/openerp/modules/migration.py
index 4ded70ffcb2..09595336eaa 100644
--- a/openerp/modules/migration.py
+++ b/openerp/modules/migration.py
@@ -22,31 +22,15 @@
 
 """ Modules migration handling. """
 
-import os, sys, imp
+import imp
+import logging
+import os
 from os.path import join as opj
-import itertools
-import zipimport
 
 import openerp
-
-import openerp.osv as osv
-import openerp.tools as tools
-import openerp.tools.osutil as osutil
-from openerp.tools.safe_eval import safe_eval as eval
-from openerp.tools.translate import _
-
-import zipfile
 import openerp.release as release
+import openerp.tools as tools
 
-import re
-import base64
-from zipfile import PyZipFile, ZIP_DEFLATED
-from cStringIO import StringIO
-
-import logging
-
-import openerp.modules.db
-import openerp.modules.graph
 
 _logger = logging.getLogger(__name__)
 
@@ -100,9 +84,10 @@ class MigrationManager(object):
 
     def migrate_module(self, pkg, stage):
         assert stage in ('pre', 'post')
-        stageformat = {'pre': '[>%s]',
-                       'post': '[%s>]',
-                      }
+        stageformat = {
+            'pre': '[>%s]',
+            'post': '[%s>]',
+        }
 
         if not (hasattr(pkg, 'update') or pkg.state == 'to upgrade'):
             return
@@ -129,9 +114,10 @@ class MigrationManager(object):
             m = self.migrations[pkg.name]
             lst = []
 
-            mapping = {'module': opj(pkg.name, 'migrations'),
-                       'maintenance': opj('base', 'maintenance', 'migrations', pkg.name),
-                      }
+            mapping = {
+                'module': opj(pkg.name, 'migrations'),
+                'maintenance': opj('base', 'maintenance', 'migrations', pkg.name),
+            }
 
             for x in mapping.keys():
                 if version in m[x]: