Sam,
I've tried to use that code. But in Power BI visuals CLI tool there's no objects, used in HierarchySlicer: utility.SelectionManager, ITreeView, IInteractiveBehavior, ISelectionHandler, etc. Apparently that visual was developed by the web tool. And this is another one problem: code for web-tool is different from that is described in Power BI visuals CLI tool. Considering web-tool now is not recommended and not supported, code for it doesn't make sense.