# -*- coding: utf-8 -*-
##############################################################################
#
#    OpenERP, Open Source Management Solution
#    This module copyright (C) 2013 Therp BV (<http://therp.nl>).
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################
from openerp.osv import orm


class accountInvoice(orm.Model):
    _inherit = 'account.invoice'

    def onchange_partner_id(
            self, cr, uid, ids, type, partner_id,
            date_invoice=False, payment_term=False,
            partner_bank_id=False, company_id=False):
        """
        Replace the selected partner with the preferred invoice contact
        """
        if partner_id:
            partner_invoice_id = self.pool.get('res.partner').address_get(
                cr, uid, [partner_id], adr_pref=['invoice'])['invoice']
            if partner_invoice_id != partner_id:
                result = self.onchange_partner_id(
                    cr, uid, ids, type, partner_invoice_id,
                    date_invoice=date_invoice, payment_term=payment_term,
                    partner_bank_id=partner_bank_id, company_id=company_id)
                result['value']['partner_id'] = partner_invoice_id
                return result
        return super(accountInvoice, self).onchange_partner_id(
            cr, uid, ids, type, partner_id,
            date_invoice=date_invoice, payment_term=payment_term,
            partner_bank_id=partner_bank_id, company_id=company_id)

# -*- coding: utf-8 -*-
##############################################################################
#
#    OpenERP, Open Source Management Solution
#    This module copyright (C) 2013 Therp BV (<http://therp.nl>).
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################
from openerp.osv import orm


class AccountInvoice(orm.Model):
    _inherit = 'account.invoice'

    def onchange_partner_id(
            self, cr, uid, ids, type, partner_id,
            date_invoice=False, payment_term=False,
            partner_bank_id=False, company_id=False):
        """
        Replace the selected partner with the preferred invoice contact
        """
        partner_invoice_id = partner_id
        if partner_id:
            partner_invoice_id = self.pool.get('res.partner').address_get(
                cr, uid, [partner_id], adr_pref=['invoice'])['invoice']
        result = super(AccountInvoice, self).onchange_partner_id(
            cr, uid, ids, type, partner_invoice_id,
            date_invoice=date_invoice, payment_term=payment_term,
            partner_bank_id=partner_bank_id, company_id=company_id)
        if partner_invoice_id != partner_id:
            result['value']['partner_id'] = partner_invoice_id
        return result

Simplify the logic and remove nonsense restart of the inheritance chain. Fix class name capitalization