Writing the extensions like rx

gistfile1.txt

// Extention
extension UILabel {
    func color(_ color: UIColor)->UILabel {
        self.textColor = color
        return self
    }
    
    func font(_ name: String = "Helvetica ", size: CGFloat = 10)->UILabel  {
        self.font = UIFont(name: name, size: size)
        return self
    }
}

// Ussage
let label = UILabel()
label
    .color(UIColor.red)
    .font("Helvetica", size: 12)