diff --git a/addons/account/invoice.py b/addons/account/invoice.py
index efbf3605059..44aea3466e6 100644
--- a/addons/account/invoice.py
+++ b/addons/account/invoice.py
@@ -860,8 +860,7 @@ class account_invoice(osv.osv):
             if totlines:
                 res_amount_currency = total_currency
                 i = 0
-                ctx = context.copy()
-                ctx.update({'date':inv.date_invoice})
+                ctx.update({'date': inv.date_invoice})
                 for t in totlines:
                     if inv.currency_id.id != company_currency:
                         amount_currency = cur_obj.compute(cr, uid, company_currency, inv.currency_id.id, t[1], context=ctx)