@api.multi
def _is_event_registrable(self):
    self.ensure_one()
    if (not self.event_ticket_ids):
        return True
    return all(self.event_ticket_ids.with_context(active_test=False).mapped((lambda t: t.product_id.active)))
@api.multi
def _is_event_registrable(self):
    self.ensure_one()
    if (not self.event_ticket_ids):
        return True
    return all(self.event_ticket_ids.with_context(active_test=False).mapped((lambda t: t.product_id.active)))