Prevent more than one instance of the game?

I want to prevent the user to execute more than one instance of my game.
how can i achieve this with panda3d?
I’m currently using pywin32api, but deploy-ng doesn’t support it for compiling to executable.
now, how can i use panda3d’s implementation to achieve this goal?
should i use mutexes, if yes, how? if no, what should i use instead?
thanks in advance.