code: func (o UUID) MarshalText() ([]byte, error) {
  	f := FormatCanonical
  	if defaultFormats[printFormat] {
  		f = printFormat
  	}
  	return []byte(formatUuid(o.Bytes(), f)), nil
  }
docs: // MarshalText implements the encoding.TextMarshaler interface. It will marshal
  // text into one of the known formats, if you have changed to a custom Format
  // the text be output in canonical format.