Is there a way to modify the LiftGammaGain via code?

Using this aint working:

Code (CSharp):

1.  LiftGammaGain liftGammaGain;
2.                 if (volume.profile.TryGetSettings(out liftGammaGain))
3.                 {
4.                     liftGammaGain.gamma=new value;
5.                 }