Closing gtabview window without user clicking the close button

System: windows 10
Python: 3.9

Hi, gtabview is working fine but I was wondering if there's a way to close the window using code without the user clicking the close button? 

Usually, a process has its PID (eg available using psutil), but when I run gtabview in a jupyter notebook, the PID for the gtabview window is not shown.

Please assist me with this. Thank you.