How to Set State/StateMechine' postion in Controller by script

I trying to set a new position for state/stateMechine , but It doesn't work...... here is what I try to do And I don't know why...

 void SetClipPosition(UnityEditor.Animations.AnimatorController ctrl)
 {
     foreach (UnityEditor.Animations.AnimatorControllerLayer layer in ctrl.layers)
     {
         int y = 0;
         for (int i = 0; i <layer.stateMachine.states.Length; i++)
         {
             y = i*50;
             layer.stateMachine.states[i].position = new Vector3(0, y, 0);
         }
         for (int i = 0; i <layer.stateMachine.stateMachines.Length; i++)
         {
             y = i*50;
             layer.stateMachine.stateMachines[i].position = new Vector3(30, y, 0);
         }
     }
     string ctrlpth = AssetDatabase.GetAssetPath(ctrl);
     AssetDatabase.WriteImportSettingsIfDirty(ctrlpth);
 }