swift中的多行多色属性文本

let mutableAttributedString = NSMutableAttributedString()

let regularAttribute = [NSAttributedStringKey.font: UIFont(name: "Avenir-Light", size: 45.0), NSAttributedStringKey.foregroundColor: UIColor.yellow]
let boldAttribute = [NSAttributedStringKey.font: UIFont(name: "Avenir-Light", size: 25.0), NSAttributedStringKey.foregroundColor: UIColor.white]     

let mutableAttributedString2 = NSMutableAttributedString()
let boldAttributedString = NSAttributedString(string: "person", attributes: boldAttribute)
let regularAttributedString = NSAttributedString(string: "\(self.requestCount)", attributes: regularAttribute)
mutableAttributedString2.append(boldAttributedString)
mutableAttributedString2.append(NSAttributedString(string: "\n"))
mutableAttributedString2.append(regularAttributedString)

self.btnStatsPeople.setAttributedTitle(mutableAttributedString2, for: .normal)