在Swift中以编程方式将标签添加到消息应用程序？

import Messages

class MessagesViewController: MSMessagesAppViewController {
    // ...
}

override func willBecomeActive(with conversation: MSConversation) {
    super.willBecomeActive(with: conversation)
    
    // 创建标签
    let label = UILabel()
    label.text = "Hello, World!"
    label.textColor = .white
    label.backgroundColor = .blue
    label.textAlignment = .center
    
    // 添加标签到视图
    self.view.addSubview(label)
    
    // 设置标签的约束
    label.translatesAutoresizingMaskIntoConstraints = false
    label.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
    label.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
    label.widthAnchor.constraint(equalToConstant: 200).isActive = true
    label.heightAnchor.constraint(equalToConstant: 50).isActive = true
}