Stored properties in Swift Extensions in Swifty way

StoredPropertiesExtenstion.swift

import Foundation
import UIKit

extension CustomView {
    
    // can make private
    static let storedProperties = WeakDictionary<UIView, Properties>()
    
    struct Properties {
        var url: String = ""
        var status = false
        var desc: String { "url: \(url), status: \(status)" }
    }
    
    var properties: Properties {
        get {
            return CustomView.storedProperties.get(forKey: self) ?? Properties()
        }
        set {
            CustomView.storedProperties.set(forKey: self, object: newValue)
        }
    }
}

var view: CustomView? = CustomView()
print("1 print", view?.properties.desc ?? "nil")
view?.properties.url = "abc"
view?.properties.status = true
print("2 print", view?.properties.desc ?? "nil")
view = nil

WeakDictionary.swift

import Foundation
import UIKit

private class WeakHolder<T: AnyObject>: Hashable {
    weak var object: T?
    let hash: Int

    init(object: T) {
        self.object = object
        hash = ObjectIdentifier(object).hashValue
    }

    func hash(into hasher: inout Hasher) {
        hasher.combine(hash)
    }

    static func ==(lhs: WeakHolder, rhs: WeakHolder) -> Bool {
        return lhs.hash == rhs.hash
    }
}

class WeakDictionary<T1: AnyObject, T2> {
    private var dictionary = [WeakHolder<T1>: T2]()

    func set(forKey: T1, object: T2?) {
        dictionary[WeakHolder(object: forKey)] = object
    }

    func get(forKey: T1) -> T2? {
        let obj = dictionary[WeakHolder(object: forKey)]
        return obj
    }

    func forEach(_ handler: ((key: T1, value: T2)) -> Void) {
        dictionary.forEach {
            if let object = $0.key.object, let value = dictionary[$0.key] {
                handler((object, value))
            }
        }
    }
    
    func clean() {
        var removeList = [WeakHolder<T1>]()
        dictionary.forEach {
            if $0.key.object == nil {
                removeList.append($0.key)
            }
        }
        removeList.forEach {
            dictionary[$0] = nil
        }
    }
}