[Gretl-devel] how do packages in a model window grab the $model bundle?

Hi, in the changelog of 2017b I read: "Fix bug: ensure that the $model accessor (bundle) is available to function packages that attach to a model window" And indeed I have a function here (to be packaged) that takes a $model-style bundle as an argument. How do I have to specify the function signature or argument so that it is actually the $model bundle that is automatically handed over to the package? I looked briefly in the package guide, but couldn't find an answer (I think). thanks, sven