Get vCenter entities without using the inventory service

We regularly use the "Get vCenter entities by properties" workflow to get VMs so we can bypass the unreliable Inventory service.  I'd like to also use it in a few cases to get a folder but I'm hitting an error I'm unsure how to solve.

I'm passing in a targetType of "Folder" and am getting this dunes value back:

dunes://service.dunes.ch/CustomSDKObject?id='vcenter/group-s1929'&dunesName='VC:Folder'

And when I try and convert that to a VmFolder object using: myfolderobj = Server.fromUri(dunesstring)

I get an error that says:

Unsupported type error: Unknown type: VC:Folder

I've tried to pass in "VmFolder" (with a variety of case) and that gives an error when trying to run the actual search.

Does anyone know what values are possible here for type that match a VmFolder type?

dvatov references the workflows i'm talking about here:

Return custom values through vCenter Orchestrator API