object
method private virtual connect :
'b.
([> `treesortable ] as 'a, 'b) GtkSignal.t ->
callback:'b -> GtkSignal.id
method private virtual notify :
'b. ('a, 'b) Gobject.property -> callback:('b -> unit) -> GtkSignal.id
method sort_column_changed : callback:(unit -> unit) -> GtkSignal.id
end