UI tools in Fusion 9 with PySide2

Greetings

Im new to fusion scripting with Python (Using Python 3.6) and i’m looking for a way to get the main window from my fusion instance. I’m going to wrap my PySide QWidget to it with shiboken2 wrapInstance.

so far i’ve tried ‘fusion.GetMainWindow()’ wich returns None, a baffling discovery.

Does anyone out there know what i might be looking for instead, or what i’m doing wrong?