Start with the com.pega.pegarules.pub.runtime PublicAPI interface - in an Activity java step an implicit variable named "tools" will pre-exist.

You can get at pyWorkPage using:  ClipboardPage page = tools.FindPage("pyWorkPage");

A ClipboardPage is a StringMap hence you can ask for its keySet() of Property names then iterate it.

You can instantiate each ClipboardProperty to then know its mode (scalar, page, pagelist).

This is accomplished using the ClipboardPage method:  ClipboardProperty getIfPresent(String key).

It is possible that you can skip knowing the ClipboardProperty's mode and simply attempt to iterate it after first checking whether isLightweight() returns true.

Take a loot at the pxIsInTree() Function.

This shows you how to "recurse" iterable ClipboardProperty objects without using recursion.

What you do instead is push() iterable ClipboardProperty objects onto a Stack then pop() them off.

You said you want to ignore Properties that begin with px, pz, and py.

Since you are iterating the keySet, ignore keys that have these prefixes.

    if ( ! key.startsWith("px") && ! key.startsWith("py") && ! key.startsWith("pz") )  {

   }