Add missing imports in issue240 patch

issue240_631.diff

@@ -174,6 +174,27 @@ diff -r adfc6fc08b4e locale/es_ES.po
 diff -r adfc6fc08b4e trytond/trytond/modules/stock_lot/stock.py
 --- a/trytond/trytond/modules/stock_lot/stock.py	Wed Dec 02 23:43:15 2015 +0100
 +++ b/trytond/trytond/modules/stock_lot/stock.py	Wed Dec 02 23:43:58 2015 +0100
+@@ -1,15 +1,18 @@
+ # This file is part of Tryton.  The COPYRIGHT file at the top level of
+ # this repository contains the full copyright notices and license terms.
++import datetime
+ from trytond.model import ModelView, ModelSQL, fields
+-from trytond.pyson import Eval
++from trytond.pyson import Eval, PYSONEncoder
+ from trytond.pool import Pool, PoolMeta
+ from trytond.transaction import Transaction
++from trytond.wizard import Wizard, StateView, StateAction, Button
+ from trytond.modules.stock import StockMixin
+
+ __all__ = ['Lot', 'LotType', 'Move', 'ShipmentIn', 'ShipmentOut',
+     'ShipmentOutReturn',
+     'Period', 'PeriodCacheLot',
+-    'Inventory', 'InventoryLine']
++    'Inventory', 'InventoryLine', 'Location', 'LotByLocationStart',
++    'LotByLocation']
+ __metaclass__ = PoolMeta
+
+
 @@ -224,3 +224,73 @@
          if move:
              move.lot = self.lot