GuardExample.swift

func tintColor(configData: NSDictionary) -> UIColor? {
    guard let tintColor = configData["tint_color"] as? [String: CGFloat] else {
        return nil
    }

    guard let r = tintColor["red"], g = tintColor["green"], b = tintColor["blue"] else {
        return nil
    }

    return UIColor(red: r, green: g, blue: b, alpha: 1)
}