I know more than 2 years passed, but I wanted my phone to config retropie without using a Keyboard and tested your app. From your code on Github there are 2 problems in the main .py file.
1 - You're importing 2 times subprocess, which is redundant, no big problem whatsoever here
2- There's a Syntax error on line 114 that prevented the service to start on my PI3. There aren't () both at start and end from the print command.
So I changed it, copied the file to /usr/bin/ and it worked like a charm.
