modules/purchase_trade/payment_term.py

@@ -21,6 +21,7 @@ class PaymentTermLine(metaclass=PoolMeta):
     trigger_event = fields.Selection(TRIGGERS, 'Trigger Event')
 
     term_type = fields.Selection([
+        (None, ''),
         ('advance', 'Advance'),
         ('cad', 'CAD'),
         ('open', 'Open'),
@@ -30,6 +31,7 @@ class PaymentTermLine(metaclass=PoolMeta):
 
     trigger_offset = fields.Integer('Trigger Offset')
     offset_unit = fields.Selection([
+        (None, ''),
         ('calendar', 'Calendar Days'),
         ('business', 'Business Days'),
     ], 'Offset Unit')
@@ -43,6 +45,7 @@ class PaymentTermLine(metaclass=PoolMeta):
     ], 'EOM Mode')
 
     risk_classification = fields.Selection([
+        (None, ''),
         ('fully_secured', 'Fully Secured'),
         ('partially_secured', 'Partially Secured'),
         ('unsecured', 'Unsecured'),