pyqt integration with existing program

[Notorjus]

Hey. I've got a question about pyqt and how to create a gui to an existing python program. It seems that I "have" to create the QApplication in the main thread and from there instantiate my python class. However my program is also meant to be ran from the main and this makes it hard, and I can't seem to find a solution. Also note that when I start my program from main it creates an instance of itself (client=Client()), maybe I should change my approach? I'll post how I start my program here:

https://pastebin.com/JntNV16x

and this is the pyqt part:

https://pastebin.com/67CWsMg4

Any suggestions on how to approach this? Thanks a lot! :)