Connect SQ LITE 3 with Eto form

I have code with sqlite 3 with python. It include 2 class with eto form is “PRIN” and “STAB”
(Class “STAB” only for call show modal for class “PRIN”) and 1 database ‘STAB.db’ with sq lite 3 (Just “PRIN” connect with database).
If i run for class “PRIN” dont throught class “STAB” by button so it is ok.
I want to run class “PRIN” by click button of class “STAB”. Please hellp me.
Below is all of code by python. (6.8 KB)

Who can help me. Plesea.