SetParameterbyname of a wall

Hi guys, so im am trying to set the “Room Bounding” parameter of all walls of X type to zero.

So i am trying to get “wall types”
But i am getting error, see attached image

“Room Bounding” is an instance parameter. You need to get the instances not the type in this case. Either get all elements of type or get all elements of category and filter out by the type.