如何在MKMapView上使用不同的笔画/颜色绘制2个MKPolyline？

import MapKit

class ViewController: UIViewController, MKMapViewDelegate {
    @IBOutlet weak var mapView: MKMapView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置地图视图的代理
        mapView.delegate = self
        
        // 创建两个MKPolyline对象
        let coordinates1 = [CLLocationCoordinate2D(latitude: 40.7128, longitude: -74.0060),
                            CLLocationCoordinate2D(latitude: 34.0522, longitude: -118.2437)]
        let polyline1 = MKPolyline(coordinates: coordinates1, count: coordinates1.count)
        
        let coordinates2 = [CLLocationCoordinate2D(latitude: 37.7749, longitude: -122.4194),
                            CLLocationCoordinate2D(latitude: 47.6062, longitude: -122.3321)]
        let polyline2 = MKPolyline(coordinates: coordinates2, count: coordinates2.count)
        
        // 添加两个MKPolyline对象到地图视图
        mapView.addOverlay(polyline1)
        mapView.addOverlay(polyline2)
    }
    
    // MKMapViewDelegate方法：返回MKPolylineRenderer对象
    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        if let polyline = overlay as? MKPolyline {
            // 创建MKPolylineRenderer对象
            let renderer = MKPolylineRenderer(polyline: polyline)
            
            // 判断是哪个MKPolyline对象，设置对应的笔画/颜色
            if polyline === polyline1 {
                renderer.strokeColor = .red
                renderer.lineWidth = 3
            } else if polyline === polyline2 {
                renderer.strokeColor = .blue
                renderer.lineWidth = 2
            }
            
            return renderer
        }
        
        return MKOverlayRenderer()
    }
}