如何在按钮内自动布局约束通知标签？

// 创建按钮
let button = UIButton()
button.setTitle("按钮", for: .normal)
button.backgroundColor = .blue
button.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(button)

// 创建通知标签
let label = UILabel()
label.text = "通知"
label.backgroundColor = .red
label.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(label)

// 设置按钮约束
NSLayoutConstraint.activate([
    button.topAnchor.constraint(equalTo: view.topAnchor, constant: 20),
    button.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
    button.widthAnchor.constraint(equalToConstant: 100),
    button.heightAnchor.constraint(equalToConstant: 50)
])

// 设置通知标签约束
NSLayoutConstraint.activate([
    label.topAnchor.constraint(equalTo: button.topAnchor),
    label.leadingAnchor.constraint(equalTo: button.trailingAnchor, constant: 10),
    label.widthAnchor.constraint(equalToConstant: 80),
    label.heightAnchor.constraint(equalToConstant: 30)
])