public void AddEventHandler(Delegate? handler, [CallerMemberName] string eventName = null)
{
	ArgumentNullException.ThrowIfNull(eventName);
	ArgumentNullException.ThrowIfNull(handler)
	var methodInfo = handler.GetMethodInfo() ?? throw new NullReferenceException("Could not locate MethodInfo");
	AddEventHandler(eventName, handler.Target, methodInfo, eventHandlers);
}
public void RemoveEventHandler(Delegate? handler, [CallerMemberName] string eventName = "")
{
	ArgumentNullException.ThrowIfNull(eventName);
	ArgumentNullException.ThrowIfNull(handler)
	var methodInfo = handler.GetMethodInfo() ?? throw new NullReferenceException("Could not locate MethodInfo");
	RemoveEventHandler(eventName, handler.Target, methodInfo, eventHandlers);
}

readonly WeakEventManager weakEventManager = new WeakEventManager();
event PropertyChangedEventHandler? INotifyPropertyChanged.PropertyChanged
{
    add => weakEventManager.AddEventHandler(value);
    remove => weakEventManager.RemoveEventHandler(value);
}
void OnPropertyChanged([CallerMemberName] in string propertyName = "") => weakEventManager.HandleEvent(this, new PropertyChangedEventArgs(propertyName), nameof(INotifyPropertyChanged.PropertyChanged));

var weakEvent = new WeakEventListener<INotifyCollectionChanged, object, NotifyCollectionChangedEventArgs>(valNotifyCollection)
{
    OnEventAction = (instance, source, args) => obj.SetActive(IsNullOrEmpty(instance)),
    OnDetachAction = (weakEventListener) => valNotifyCollection.CollectionChanged -= weakEventListener.OnEvent
};