Code review comment for lp:~roberto-v/account-payment/adding_account_vat_on_payment_7

Ciao Roberto,
many thanks for your contribution.

Some remarks:
 - Why is default_has_vat_on_payment a selection instead of a boolean?
 - Now, if the vat_on_payment invoice field is (correctly) set by the onchange_partner_id method, probably the _get_vat_on_payment method should be used to set the default value of default_has_vat_on_payment when creating new partners
 - Please run a PEP8 validator on your code