code: func iptablesFlush(ipt iptables.Interface) error {
  	el := []error{}
  	if err := ipt.FlushChain(iptables.TableNAT, iptablesContainerPortalChain); err != nil {
  		el = append(el, err)
  	}
  	if err := ipt.FlushChain(iptables.TableNAT, iptablesHostPortalChain); err != nil {
  		el = append(el, err)
  	}
  	if err := ipt.FlushChain(iptables.TableNAT, iptablesContainerNodePortChain); err != nil {
  		el = append(el, err)
  	}
  	if err := ipt.FlushChain(iptables.TableNAT, iptablesHostNodePortChain); err != nil {
  		el = append(el, err)
  	}
  	if err := ipt.FlushChain(iptables.TableFilter, iptablesNonLocalNodePortChain); err != nil {
  		el = append(el, err)
  	}
  	if len(el) != 0 {
  		klog.Errorf("Some errors flushing old iptables portals: %v", el)
  	}
  	return utilerrors.NewAggregate(el)
  }
docs: // Flush all of our custom iptables rules.