How to set TreeVertex.level manually ? Any example?

I want to know how to set TreeVertex.level manually. Is there any example ?

I thought I provided a complete sample at How to bypass node level in GoJS?.

And there is the possible alternative requirement in the existing sample:

TreeLayout works on a tree-structured graph that is in a TreeNetwork composed of TreeVertexs and TreeEdges. It automatically computes the TreeVertex.level property based on the graph. But the code I gave you (posted in the other topic) adjusts the level based on the value of the property.