Fix guidelines

statement.py

@@ -3,8 +3,10 @@
 from trytond.osv import fields, OSV, ExceptORM
 from trytond.netsvc import LocalService
 from decimal import Decimal
+
 _STATES = {'readonly': 'state != "draft"'}
 
+
 class Statement(OSV):
     'Bank Statement'
     _name = 'statement.statement'
@@ -172,6 +174,7 @@ class Statement(OSV):
 
 Statement()
 
+
 class Line(OSV):
     'Bank Statement Line'
     _name = 'statement.statement.line'