How to stop multiple instances of sound when you click a button

AS3: Obviously, I’m a newbie :stare:

I’d like to stop my movie from playing multiple instances of a sound every time I click a button.

click button > play (3sec) sound. << i can handle that part, i think.

BUT, i’d like to check if the sound is playing…
If so, don’t play a second instance of the sound.
Else, play the sound.

Does that make sense?
Thank you!!