How can I insert the obliv-c executable code into python and get the output？

[SakataGintokiAlways]

I want to use obliv-c to build a small protocol in my whole program which is coded by python. This protocol is semi-honest GC so the command consists of cycle and a.out. When I insert this command in my python code and use popen to get the output, i can only get None (result from cycle i think) and cannot get the result computed by a.out. I tried to redirect but cannot solve this problem. Is there any solutions to help me get the result in python?