Assign material to mass by room type

Hello everyone. This is my first post. I am trying to create a space planning script and have it largely working except I cant for the life of me figure out how to connect my room type list so that I don’t get a null list or error.
The masses are created from my excel spreadsheet so if I can get the materials mapped I will have some nice colour coding - Screenshot attached - let me know if you need the revit file or the excel file

the picture you posted is unreadable, to fix that, zoom in on a single node so you can read what it is, then click on the camera button.


Thanks Marcel for your prompt reply. I have solved this in the interim. Solution as follows:
I upgraded my Dynamo install to latest version 2.01 - Re-installed latest ReAnimation and Clockwork packages.
I attach an image of the Clockwork switch node.
The simple fix was that I had my Cases and Values connections around the wrong way.
The image shown is now correct - so I can mark this as solved.
Regards to all.