The power of Color Sets in Xcode9

Colors.swift

enum AppColor:String {
    case AppClearColor
    case AppGrayColor
    case AppWhiteColor
    case PrimaryColor
    case PrimaryColor1
    case PrimaryColor2
    case PrimaryColor3
    case SecondaryColor1
    case ThemeColor
}

extension AppColor {
    var color: UIColor {
        get {
            return UIColor(named: self.rawValue)!
        }
    }
}