There is a problem with return types while extending Bot class

[Vanawy]

I extend Bot class then add new onSomething method.
I call one of default on methods and then I call child method onSomething
Intellisense tells there is no method 'onSomething' because in Bot class in all 'on' methods return type is Bot.

I suggest to change return type to self instead of \Viber\Bot