为UILabel设置渐变背景色错误

import UIKit

extension UILabel {
    func setGradientBackground(colors: [UIColor], startPoint: CGPoint, endPoint: CGPoint) {
        let gradientLayer = CAGradientLayer()
        gradientLayer.frame = bounds
        gradientLayer.colors = colors.map { $0.cgColor }
        gradientLayer.startPoint = startPoint
        gradientLayer.endPoint = endPoint
        layer.insertSublayer(gradientLayer, at: 0)
    }
}

// 使用示例
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
label.text = "Hello World"
label.textAlignment = .center
label.setGradientBackground(colors: [UIColor.red, UIColor.blue], startPoint: CGPoint(x: 0, y: 0), endPoint: CGPoint(x: 1, y: 0))