无法在UICollectionView中修改UILabel框架？

class CustomCell: UICollectionViewCell {
    var label: UILabel!
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        label = UILabel(frame: bounds)
        label.textAlignment = .center
        addSubview(label)
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        label.frame = bounds
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}