Hello I am trying to make an on change. Everything is ok, The field call the method and all. BUt when this had that feed another field this give me error:

I am trying to feed a relational(Many2one) with the results of a query. Here is my code:

    invoice = fields.Many2one('account.invoice', string='Factura')
    client = fields.Many2one('res.partner', string='Cliente', domain=[('customer', '=', True)])

    @api.onchange('client')
    def _searchInvoice(self):
        if self.client is not None:
            invoice = self.env['account.invoice'].search([('type', '=', 'out_invoice'),
                                                           ('partner_id', '=', self.client.id)])
            self.invoice = invoice