It is important to call this function in the instance initializer
of a gtk.widget.Widget subclass and not in GObject.constructed() or
GObject.constructor() for two reasons:
derived widgets will assume that the composite widgets
defined by its parent classes have been created in their
relative instance initializers
when calling [gobject.object.ObjectG.new_] on a widget with composite templates,
it’s important to build the composite widgets before the construct
properties are set. Properties passed to [gobject.object.ObjectG.new_] should
take precedence over properties set in the private template XML
A good rule of thumb is to call this function as the first thing in
an instance initialization function.
Creates and initializes child widgets defined in templates.
This function must be called in the instance initializer for any class which assigned itself a template using gtk.widget_class.WidgetClass.setTemplate.
It is important to call this function in the instance initializer of a gtk.widget.Widget subclass and not in GObject.constructed() or GObject.constructor() for two reasons:
A good rule of thumb is to call this function as the first thing in an instance initialization function.