Trying to get ColumnView to work gtk4

[Eric C. <bea...@ya...>]

Im trying to switch to gtk4's new ColumnView.
However, when I try this:
    store = Gio::ListStore.new(DataObject)
it gives an error because DataObject must be a subclass of GObject
So my class definition:
    class DataObject < GObject
does't find the Name GObject
How to I reference GOObject?  Where is it?
Do I need these:```      require "gio"      require "gio2"```Then where is GObject?
Gio::GObject  (fails)GObject::Gobject (fails)GObject::Object (fails)
I've looked everytwhere.
please fix this line of code:
    class DataObject < GObject

Thanks, and I when I write a simple example for a TreeView, I will submit it to the samples directory.
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