This function is called when implementing subclasses of #AtkObject.
It does initialization required for the new object. It is intended
that this function should called only in the ..._new() functions used
to create an instance of a subclass of #AtkObject
This function is called when implementing subclasses of #AtkObject. It does initialization required for the new object. It is intended that this function should called only in the ..._new() functions used to create an instance of a subclass of #AtkObject