"Data conversion failed from Goo to Brep"

Trying to write a simple mass analysis GH script, utilizing Human UI.
There’s a Pick button in the Human UI window, which I use to get some breps from the Rhino scene. The Values component is plugged into PickBtn, giving the GUIDs.
My problem is, how do I get the actual breps from the GUIDs. There’s a simple Python component that does that:

I’d like to plug those breps into a Brep|Plane section component, and get this error.
What do I need to do?
Thanks a lot!!

mass floors debug.gh (22.1 KB)

Try passing the guids into a brep parameter

That simple! Thank you, Andrew!!