code: func (m MACCommands) MarshalBinary() ([]byte, error) {
  	var out []byte
  	for _, mac := range m {
  		b, err := mac.MarshalBinary()
  		if err != nil {
  			return nil, err
  		}
  		out = append(out, b...)
  	}
  	return out, nil
  }
docs: // MarshalBinary implements the encoding.BinaryMarshaler interface.