Cast Structural column family to family type

Hi Dynamo forum.
I am working on modeling rebar using dynamo, and I am currently design for a node that receives user input.

The problem is, node(Family.Type) which I use for get family type (Structural column family) is donot working.

The node said(can see in image) was called from structuralFraming so cannot do those work!

As you know, Structural Column “Family” is also family too.

What can i do?