diff --git a/addons/account_voucher/voucher_payment_receipt_view.xml b/addons/account_voucher/voucher_payment_receipt_view.xml
index 1169d5ef7c3..b4578c9b035 100644
--- a/addons/account_voucher/voucher_payment_receipt_view.xml
+++ b/addons/account_voucher/voucher_payment_receipt_view.xml
@@ -334,7 +334,7 @@
                                 <field name="writeoff_amount" widget="monetary" options="{'currency_field': 'currency_id'}"/>
                                 <field name="payment_option" required="1" attrs="{'invisible':[('writeoff_amount','=',0)]}"/>
                                 <field name="writeoff_acc_id"
-                                        attrs="{'invisible':['|', ('payment_option','!=','with_writeoff'), ('writeoff_amount','=',0)], 'required':[('payment_option','=','with_writeoff')]}"
+                                        attrs="{'invisible':['|', ('payment_option','!=','with_writeoff'), ('writeoff_amount','=',0)], 'required':[('payment_option','=','with_writeoff'), ('writeoff_amount','!=',0)]}"
                                         domain="[('type','=','other')]"/>
                                 <field name="comment"
                                         attrs="{'invisible':['|', ('payment_option','!=','with_writeoff'), ('writeoff_amount','=',0)]}"/>
diff --git a/openerp/osv/fields.py b/openerp/osv/fields.py
index 8f5ea710433..37f1b0916b1 100644
--- a/openerp/osv/fields.py
+++ b/openerp/osv/fields.py
@@ -1225,7 +1225,7 @@ class function(_column):
         if values and not multi and name in values[0]:
             result = {v['id']: v[name] for v in values}
         elif values and multi and all(n in values[0] for n in name):
-            result = {v['id']: dict({n: v[n]} for n in name) for v in values}
+            result = {v['id']: dict((n, v[n]) for n in name) for v in values}
         else:
             result = self._fnct(obj, cr, uid, ids, name, self._arg, context)
         for id in ids: