How to edit particle system size over lifetime curve with script?

I'm trying to add a flickering effect the the particles in the particle system, so I thought I'd use a script to toggle the size between 0 & 1 in the size over lifetime curve. So I tried

 public int flickerCount;
 
     // Use this for initialization
     void Start () {
         ParticleSystem part = gameObject.GetComponent<ParticleSystem>();
         float length = part.main.duration;
         float timeInc = 1/(flickerCount*2);
         ParticleSystem.SizeOverLifetimeModule sizeSettings = part.sizeOverLifetime;
         ParticleSystem.MinMaxCurve sizeCurve = sizeSettings.size;
         AnimationCurve aCurve = sizeCurve.curve;
 
         for(int i = 0; i < flickerCount*2+1; i++)
         {
             Keyframe kf = new Keyframe();
             if(i % 2 == 0)
             {
                 kf.value = 1;
             }else
             {
                 kf.value = 0;
             }
             kf.time = i * timeInc;
             aCurve.AddKey(kf);
         }
 
         sizeCurve.curve = aCurve;
         sizeSettings.size = sizeCurve;
     }

But it didn't seem to have any affect. Is there some other way I should use to edit the curve?