Feat:Se agrega vista a 'sale_form

sale.py

@@ -1,6 +1,5 @@
 from trytond.pool import PoolMeta, Pool
 from trytond.model import fields, ModelSQL, ModelView
-from trytond.pyson import Eval
 from trytond.transaction import Transaction
 
 
@@ -12,7 +11,7 @@ class Sale(metaclass=PoolMeta):
         'sale',
         "Delete lines",
         states={
-            'readonly': Eval('state') != 'draft'
+            'readonly': True
         }
     )