Run an active window inside an PyQT5 GUI application

Hello! I'm using PyQT5, and I want to run an external window inside a TabWidget, something similar to that, but this example is for Windows only, and I want to run in a Linux (Ubuntu 14.04) os. This question is very similar to mine, but I didn't find the solution. Also, find a similar problem (the exact thing I want to do) in this thread but the answers didn't work. Also tried the solution here but didn't work either. I know that is possible to embed a terminal, like this code, but i have no idea how to do the same with the "RViz" shell command.

I already tried to open the rviz win alone, acquiring his ID with the wmctrl command (wmctrl -l | grep -i RViz | awk '{print $1}') via shell and used his ID parsed to winID (i copy and pasted the value) class from PyQT, doesn't work either. I think that maybe is my code because some people do that in windows using the win32gui module. My code can be found here, someone can help me with that, please?

Don't double post. You asked the question once in the Newbie section. All of us read every new post no matter where it appears.