PyGTK - notifications inside a window. How?

Question

Python

Hello,

Can anyone tell me how to make "pop-up notifications" inside the window ?
I tried to do it with PyCairo.show_text + rectangle, but this option could not be completed,
because I could not clear the drawn area, and it's not very convenient.

There is an idea to make a special window and name it for example "InformationWindow" and place it in the main window,
but I did not find how to make "window inside window" in gtk.

Guys, tell me in which direction to dig / look.
Maybe there are ready-made solutions.

Thank you.