code: func EnsureJumpRule(fromChain, toChain string) error {
  	var (
  		table = Filter
  		args  = []string{"-j", toChain}
  	)
  
  	if Exists(table, fromChain, args...) {
  		err := RawCombinedOutput(append([]string{"-D", fromChain}, args...)...)
  		if err != nil {
  			return fmt.Errorf("unable to remove jump to %s rule in %s chain: %s", toChain, fromChain, err.Error())
  		}
  	}
  
  	err := RawCombinedOutput(append([]string{"-I", fromChain}, args...)...)
  	if err != nil {
  		return fmt.Errorf("unable to insert jump to %s rule in %s chain: %s", toChain, fromChain, err.Error())
  	}
  
  	return nil
  }
docs: // EnsureJumpRule ensures the jump rule is on top