Forming solids with different heights from polylines in a dwg

Hello, I’m quite new to Dynamo and I’m developing a context model which should include a basic massing of surrounding buildings (just as simple boxes). I have a dwg which contains polylines of these buildings, located vertically at the heights of each buildings. I’m basically trying to filter the building layer from the dwg and extrude the polylines as solids. I’ve created the path shown below, but nothing is generating and I’m not sure what else to include. Any help would be appreciated, thanks!