how to set focus when running a script using subprocess

[Malt]

Using Django I have designed a web page and I'm running a python script which will use subprocess to start windows application.
I'm facing issue here, when I click on the web page, at the backend execution of the python script is starting, however window focus is still on the web page and it is not moving to the thread which is launched by the subprocess and because of that my script is failing.

Any help on how to set focus for subprocess or any way to change the focus point when running using Django.