code: func (n *NII) UnmarshalBinary(b []byte) error {
  	// Length must be exactly 3
  	if len(b) != 3 {
  		return io.ErrUnexpectedEOF
  	}
  
  	n.Type = b[0]
  	n.Major = b[1]
  	n.Minor = b[2]
  
  	return nil
  }
docs: // UnmarshalBinary unmarshals a raw byte slice into a NII.
  //
  // If the byte slice is not exactly 3 bytes in length, io.ErrUnexpectedEOF
  // is returned.