Always add the amount to an expression

Hello there 🙂

I try to write an expression where I take the Output from Trapcodes Soundkeys (value depends on audio but the keyframes have a value from 0 to 100) and always add those to a moving object parameter - something which you can apply inifite value like rotation (in my case the offset from 3D Stroke).

Because when I write a simple: v = v + "Soundkeys.output" the movement is increasing but also decreases back.

Thanks in advance