How to indicate whether a node is a so-called partial node or not in a PartialLayouter

Hi!

I want to use the PartialLayouter for my graph. But I don't know how to indicate whether a node is a so-called partial node or not. I can't find the DataProvider Key "AFFECTED_NODES_DPKEY" for marking the partial nodes. Where can I find that key? Or is there another way to mark the nodes?

Thanks for your help.