I have stumbled across the same problem today and managed to solve it with a hscript command within python
https://www.sidefx.com/docs/houdini/commands/opdepend.html [www.sidefx.com]
so
hou.hscript("opdepend -d -e " + node.path())
should give you a list of dependency nodes.
cheers
thanks to everyone at sidefx and to the whole community, Ur was such an inspiring event
