Undocumented in source.
The gtk.TreeSelection object is a helper object to manage the selection for a gtk.TreeView widget. The gtk.TreeSelection object is automatically created when a new gtk.TreeView widget is created, and cannot exist independently of this widget. The primary reason the gtk.TreeSelection objects exists is for cleanliness of code and API. That is, there is no conceptual reason all these functions could not be methods on the gtk.TreeView widget instead of a separate function.