code: func filterNilColors(colors []color.Color) []color.Color {
  	var cleanColors []color.Color
  	for _, c := range colors {
  		if c != nil {
  			cleanColors = append(cleanColors, c)
  		}
  	}
  
  	return cleanColors
  }
docs: // filterNilColors strips any nil color.Color values from the input slice.