https://lists.gnome.org/archives/gtkmm-list/2009-April/msg00105.html
Re: Why Gtk::Builder::get_widget(_derived) returns void?
get widgetgtkbuilderderivedreturns
https://gnome.pages.gitlab.gnome.org/gtk/gtk4/method.Dialog.get_widget_for_response.html
Gtk.Dialog.get_widget_for_response
get widgetgtkdialogresponse
https://docs.gtk.org/gtk3/method.Widget.get_margin_top.html
Gtk.Widget.get_margin_top
gtkwidgetmargintop
https://daan.dev/blog/magento/grandtotal-subtotal-vat-magento-minicart/
Get Total Price of Cart Including/Excluding VAT/Tax in Magento Minicart Widget - Daan.dev