diff --git a/document_page_approval/models/document_page_history.py b/document_page_approval/models/document_page_history.py
index b1d4ee69..d769d6d2 100644
--- a/document_page_approval/models/document_page_history.py
+++ b/document_page_approval/models/document_page_history.py
@@ -102,9 +102,8 @@ class DocumentPageHistory(models.Model):
                     'You are not authorized to do this.\r\n'
                     'Only approvers with these groups can approve this: '
                     ) % ', '.join(
-                        [g.display_name 
-                        for g in rec.page_id.approver_group_ids])
-                    )
+                        [g.display_name
+                            for g in rec.page_id.approver_group_ids]))
             # Update state
             rec.write({
                 'state': 'approved',