code: func (w *Writer) getColorer() (colorer, error) {
  	switch w.ColorMode {
  	case ColorModeTrueColor:
  		return newTruecolorColorer(), nil
  	case ColorMode256:
  		return New256Colorer(), nil
  	case ColorMode0:
  		return New0Colorer(), nil
  	default:
  		return nil, fmt.Errorf("Invalid colorer: [%d]", w.ColorMode)
  	}
  }
docs: // getColorer will attempt to map the defined color mode, to a colorer{}