`object
method activate : callback:(unit -> unit) -> GtkSignal.id
method private virtual connect :
'b. ([> `expander ] as 'a, 'b) GtkSignal.t -> callback:'b -> GtkSignal.id
method private virtual notify :
'b. ('a, 'b) Gobject.property -> callback:('b -> unit) -> GtkSignal.id
method notify_expanded : callback:(bool -> unit) -> GtkSignal.id
method notify_label : callback:(string -> unit) -> GtkSignal.id
method notify_label_widget : callback:(GObj.widget -> unit) -> GtkSignal.id
method notify_spacing : callback:(int -> unit) -> GtkSignal.id
method notify_use_underline : callback:(bool -> unit) -> GtkSignal.id
end`