Pass a List into a code block and pass out an element of the List?

Newbie question, but there’s something I’m def not getting about code blocks or script syntax or something. I’m trying to get an old 1.x project working.

I have a ZT node that is loading properly in the dynamo UI and is receiving proper input. The node creates a List as the output, so the output from the node shows as MyData[].

I can pass that into any other node that expects a MyData[] no problem. But if I try to get MyData[0], the first element of the List to pass into another node or code block and get any property, I just get an error msg like Warning: No property called polygon on Function could be found
even though x is not a Function and polygon is a property of MyData.

I’ve tried numerous different code block syntaxes and it just doesn’t seem to know that the thing being taken out of the List and input into other nodes or code blocks is a MyData instance, not a Function (really confused as to why I get a million errors about inputs being Functions when they aren’t, it’s a broader problem than this). I did figure one thing out, that the old code was using single-item MultiReturns, which someone said doesn’t work in 2.0, but that’s only gotten me as far as getting my ZT node to pass out the MyData[] object.

This is really basic but I’m just starting and don’t get what’s going on here syntax/binding/whatever-wise. Any help would be most appreciated. Thanks!