Secuencia en línea de compras

model/purchase.py

@@ -68,7 +68,7 @@ class PurchaseOrderLine(models.Model):
     sequence = fields.Integer(
         string='Sequence',
         help="Gives the sequence of this line when displaying the"
-             " purchase order.", {'readonly': True})
+             " purchase order.", readonly= True)
 
     @api.model
     def default_get(self, fields_list):