Sets the button label for self.
If set to "" or NULL, the button won't be shown.
The button can be used with a gio.action.Action, or with the signalBanner::button-clicked signal.
the label
Sets the button label for self.
If set to "" or NULL, the button won't be shown.
The button can be used with a gio.action.Action, or with the signalBanner::button-clicked signal.