Assign/add gameobject to LOD via script

Hello!How i can assign/add gameobject to lod?
Something like this;

GameObject test; 
public LODGroup group; 
LOD lod1;
void Update() {

But i have error:cannto convert type GameObject to LOD.How i can add gameobject to lod1 via script?Thanks gives you information on how to do this. It seems you have to re-set all your lods for that LODGroup.