Migrate to python 3

sale.py

@@ -18,8 +18,7 @@ __all__ = ['Sale', 'SalePaymentForm', 'WizardSalePayment',
     'WizardSaleReconcile']
 
 
-class Sale:
-    __metaclass__ = PoolMeta
+class Sale(metaclass=PoolMeta):
     __name__ = 'sale.sale'
     payments = fields.One2Many('account.statement.line', 'sale', 'Payments')
     paid_amount = fields.Function(fields.Numeric('Paid Amount', readonly=True),

setup.py

@@ -7,10 +7,7 @@ from setuptools import setup
 import re
 import os
 import io
-try:
 from configparser import ConfigParser
-except ImportError:
-    from ConfigParser import ConfigParser
 
 MODULE2PREFIX = {}
 

statement.py

@@ -12,14 +12,12 @@ __all__ = ['Journal', 'Statement', 'Line', 'OpenStatementStart',
     'CloseStatementDone', 'CloseStatement']
 
 
-class Journal:
-    __metaclass__ = PoolMeta
+class Journal(metaclass=PoolMeta):
     __name__ = 'account.statement.journal'
     devices = fields.One2Many('sale.device', 'journal', 'Devices')
 
 
-class Statement:
-    __metaclass__ = PoolMeta
+class Statement(metaclass=PoolMeta):
     __name__ = 'account.statement'
     users = fields.Function(fields.One2Many('res.user', None, 'Users'),
         'get_users', searcher='search_users')
@@ -58,8 +56,7 @@ class Statement:
         return [('id', 'in', query)]
 
 
-class Line:
-    __metaclass__ = PoolMeta
+class Line(metaclass=PoolMeta):
     __name__ = 'account.statement.line'
     sale = fields.Many2One('sale.sale', 'Sale', ondelete='RESTRICT')
 

user.py

@@ -10,8 +10,7 @@ from trytond.pyson import Eval
 __all__ = ['User']
 
 
-class User:
-    __metaclass__ = PoolMeta
+class User(metaclass=PoolMeta):
     __name__ = "res.user"
     sale_device = fields.Many2One('sale.device', 'Sale Device',
             domain=[('shop', '=', Eval('shop'))],