gs.getSession.putProperty() in scoped application

I'm trying to use gs.getSession().putProperty() in a scoped application widget on the service portal, but I am getting  an error that "Cannot find function putProperty in object com.glide.script.fencing.ScopedGlideSession@495843."

I know that gs.getSession() can be used in a scoped app, but does anyone know if the putProperty() method specifically cannot be used in a scoped app? I cannot find any documentation at all online. I confirmed the same functionality does work in the global scope.