'This opens the xml view specified in xml_id for the current vehicle'

@api.multi
def return_action_to_open(self):

    self.ensure_one()
    xml_id = self.env.context.get('xml_id')
    if xml_id:
        res = self.env['ir.actions.act_window'].for_xml_id('fleet', xml_id)
        res.update(context=dict(self.env.context, default_vehicle_id=self.id, group_by=False), domain=[('vehicle_id', '=', self.id)])
        return res
    return False
