Detecting Key Combinations

I’ve followed the thread there:
http://www.kirupa.com/forum/showthread.php?t=211149&page=1

I understand that this class allow the script to detect when keys are pressed in combination.

But what is exactly the implementation when a key is used both in single and combination states.
Let’s say that you’ve the “q” key used alone and “shift-q”…how would one proceed to achieve this detection?

Thanks very much,