Add python 3 support

move.py

@@ -7,10 +7,10 @@ from trytond.transaction import Transaction
 
 
 __all__ = ['Move']
-__metaclass__ = PoolMeta
 
 
 class Move:
+    __metaclass__ = PoolMeta
     __name__ = 'stock.move'
 
     purchase_request = fields.Many2One('purchase.request', 'Purchase Request',

product.py

@@ -6,10 +6,10 @@ from trytond.pyson import Eval, Equal, Not
 
 
 __all__ = ['Template']
-__metaclass__ = PoolMeta
 
 
 class Template:
+    __metaclass__ = PoolMeta
     __name__ = 'product.template'
 
     direct_stock_supply = fields.Boolean('Direct Stock Supply',

purchase.py

@@ -5,10 +5,10 @@ from trytond.transaction import Transaction
 
 
 __all__ = ['PurchaseRequest']
-__metaclass__ = PoolMeta
 
 
 class PurchaseRequest:
+    __metaclass__ = PoolMeta
     __name__ = 'purchase.request'
 
     @classmethod