diff --git a/modules/purchase_trade/lot.py b/modules/purchase_trade/lot.py
index 9f42325..ac12a41 100755
--- a/modules/purchase_trade/lot.py
+++ b/modules/purchase_trade/lot.py
@@ -2786,15 +2786,15 @@ class LotInvoice(Wizard):
                 continue
             lots.append(lot)
 
-        invoice = None
+        invoice_line = None
         if self.inv.type == 'purchase':
             Purchase._process_invoice([purchase],lots,action,self.inv.pp_pur)
-            invoice = r.r_lot_p.invoice_line if r.r_lot_p.invoice_line else r.r_lot_p.invoice_line_prov
+            invoice_line = r.r_lot_p.invoice_line if r.r_lot_p.invoice_line else r.r_lot_p.invoice_line_prov
         else:
             if sale:
                 Sale._process_invoice([sale],lots,action,self.inv.pp_sale)
-                invoice = r.r_lot_p.invoice_line if r.r_lot_p.sale_invoice_line else r.r_lot_p.sale_invoice_line_prov
-        self.message.invoice = invoice
+                invoice_line = r.r_lot_p.invoice_line if r.r_lot_p.sale_invoice_line else r.r_lot_p.sale_invoice_line_prov
+        self.message.invoice = invoice_line.invoice
 
         return 'message'