Structural Search: Find expression in a particular class

Hello.

Just wondering if someone is more expert than i in using the structural search feature.

I'm trying to find a certain expression in all classes of a particular type.

There is an example template for finding methods of a particular class which works and i understand how to use it.

So this is what i tried for my search:

And many other variations and none of them work...
Is what i'm trying to do even possible?

cheers
Oliver