'confirm Advice - confirmed Advice after computing Advice Lines..'

@api.multi
def confirm_sheet(self):

    for advice in self:
        if (not advice.line_ids):
            raise UserError(_('You    can    not    confirm    Payment    advice    without    advice    lines.'))
        date = fields.Date.from_string(fields.Date.today())
        advice_year = ((date.strftime('%m') + '-') + date.strftime('%Y'))
        number = self.env['ir.sequence'].next_by_code('payment.advice')
        advice.write({'number': (((('PAY' + '/') + advice_year) + '/') + number), 'state': 'confirm'})
