Dart APIunself_styleCustomColorssourceGold sourceGold property Null safety Color? sourceGold final Implementation final Color? sourceGold; unself_style unself_style CustomColors sourceGold property CustomColors class Constructors CustomColors Properties gold goldContainer hashCode mauve mauveContainer onGold onGoldContainer onMauve onMauveContainer onVanilla onVanillaContainer runtimeType sourceGold sourceMauve sourceVanilla type vanilla vanillaContainer Methods copyWith harmonized lerp noSuchMethod toString Operators operator ==