Limiting keys pressed?

I need to limit the controls to only act off of one key at a time. Does anybody know how to limit this? As it is right now you can press combination’s of keys and it really messes up stuff.

Linking the KeySensors to a python script that checks everytime it is executed if there are two or more keys pressed and that only activates the according actuators if there is only one key pressed should help.

But maybe there is also an easier way with logic bricks.

Thanks for the help… I hope there might be a way to do it with logic, I dont know python at all.