Weakauras- Voidform stack

[Stargolem]

Hello guys,

I trying make insanity bar with custom text (stack of voidform), but i dont know how :/. I found this code:

function() 
    return stackCount(194249) 
end

but this does not work.

[bambule]

http://wowprogramming.com/docs/api/UnitBuff

function()
   local _, _, _, voidStacks, _, _, _, _, _, _, _= UnitBuff("player",GetSpellInfo(194249));
   return voidStacks;
end