Move field bank_account_required from module account_payment_partner to account_payment_mode

Make the mandate a required field on payment line when the payment method has mandate_required=True
Make the bank account a required field on payment line when the payment method has bank_account_required=True
Minor code cleanup
PEP8

account_payment_order/models/account_payment_line.py

@@ -20,6 +20,9 @@ class AccountPaymentLine(models.Model):
         related='order_id.company_currency_id', store=True, readonly=True)
     payment_type = fields.Selection(
         related='order_id.payment_type', store=True, readonly=True)
+    bank_account_required = fields.Boolean(
+        related='order_id.payment_method_id.bank_account_required',
+        readonly=True)
     state = fields.Selection(
         related='order_id.state', string='State',
         readonly=True, store=True)
@@ -127,9 +130,8 @@ class AccountPaymentLine(models.Model):
         return res
 
     @api.multi
-    def check_payment_line(self):
-        for line in self:
-            if not line.partner_bank_id:
-                raise UserError(_(
-                    'Missing Partner Bank Account on payment line %s')
-                    % line.name)
+    def draft2open_payment_line_check(self):
+        self.ensure_one()
+        if self.bank_account_required and not self.partner_bank_id:
+            raise UserError(_(
+                'Missing Partner Bank Account on payment line %s') % self.name)

account_payment_order/models/account_payment_order.py

@@ -25,6 +25,9 @@ class AccountPaymentOrder(models.Model):
         ('inbound', 'Inbound'),
         ('outbound', 'Outbound'),
         ], string='Payment Type', readonly=True, required=True)
+    payment_method_id = fields.Many2one(
+        'account.payment.method', related='payment_mode_id.payment_method_id',
+        readonly=True, store=True)
     company_id = fields.Many2one(
         related='payment_mode_id.company_id', store=True, readonly=True)
     company_currency_id = fields.Many2one(
@@ -210,7 +213,7 @@ class AccountPaymentOrder(models.Model):
             # Create the bank payment lines from the payment lines
             group_paylines = {}  # key = hashcode
             for payline in order.payment_line_ids:
-                payline.check_payment_line()
+                payline.draft2open_payment_line_check()
                 # Compute requested payment date
                 if order.date_prefered == 'due':
                     requested_date = payline.ml_maturity_date or today

account_payment_order/views/account_payment_line.xml

@@ -18,7 +18,10 @@
                     <field name="amount_currency"/>
                     <field name="currency_id"/>
                     <field name="partner_id"/>
-                    <field name="partner_bank_id" domain="[('partner_id', '=', partner_id)]"/>
+                    <field name="partner_bank_id"
+                        domain="[('partner_id', '=', partner_id)]"
+                        attrs="{'required': [('bank_account_required', '=', True)]}"/>
+                    <field name="bank_account_required" invisible="1"/>
                     <field name="communication_type"/>
                     <field name="communication"/>
                 </group>