code: func SetDefaultPolicy(table Table, chain string, policy Policy) error {
  	if err := RawCombinedOutput("-t", string(table), "-P", chain, string(policy)); err != nil {
  		return fmt.Errorf("setting default policy to %v in %v chain failed: %v", policy, chain, err)
  	}
  	return nil
  }
docs: // SetDefaultPolicy sets the passed default policy for the table/chain