BuilderCScope 
  Creates a new GtkBuilderCScope object to use with future GtkBuilder instances.
Calling this function is only necessary if you want to add custom callbacks via method@Gtk.BuilderCScope.add_callback_symbol.
Return
a new GtkBuilderCScope
constructor(gtkBuilderCScopePointer: <Error class: unknown class><<Error class: unknown class>>)(source)