eiru_account_interest/models/res_partner_interest.py

# -*- coding: utf-8 -*-
from openerp import models, fields, tools, api, _

class ResPartnerInterest(models.Model):
    _inherit = 'res.partner'

    @api.model
    def eiru_account_interest_verify(self, id):
        interest = self. env['account.interest']
        interest.get_account_invoice_interest(None,id)