How to Swizzle what looks like an init method in Swift that's really a class method in Obj-C

UIAlertAction+Swizzle.swift

typealias UIAlertActionHandler = ((UIAlertAction) -> Swift.Void)?
private struct AssociatedKeys {
    static var handler = "cc_handler"
}

private let swizzling: (UIAlertAction.Type) -> () = { action in
    // in swift this looks like an init, but in obj-c it's really actionWithTitle:style:handler class method
    let originalSelector = #selector(UIAlertAction.init(title:style:handler:))
    let swizzledSelector = #selector(UIAlertAction.action(testTitle:style:handler:)) // so swizzling an init won't work. we have to use another class method
    
    let originalMethod = class_getClassMethod(action, originalSelector)
    let swizzledMethod = class_getClassMethod(action, swizzledSelector)
    method_exchangeImplementations(originalMethod, swizzledMethod)
}

extension UIAlertAction {
    
    var handler: UIAlertActionHandler? {
       get {
            return objc_getAssociatedObject(self, &AssociatedKeys.handler) as? UIAlertActionHandler
        }
    }
    
    open override class func initialize() {
        // make sure this isn't a subclass
        guard self === UIAlertAction.self else {
            return
        }
        swizzling(self)
    }
    
    // class method, rather than convenience init, because method we're swizzling with in obj-c is a class method
    class func action(testTitle: String?, style: UIAlertActionStyle, handler: ((UIAlertAction) -> Swift.Void)? = nil) -> UIAlertAction {
        let action = UIAlertAction.action(testTitle: testTitle, style: style, handler: handler)
        if let handler = handler {
            objc_setAssociatedObject(action, &AssociatedKeys.handler, handler, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
        return action
    }
}