code: def initial(self, request, *args, **kwargs):
          
          super(InterfaceIpList, self).initial(request, *args, **kwargs)
  
          # ensure interface exists
          try:
              self.interface = Interface.objects.accessible_to(request.user)\
                          .get(pk=self.kwargs.get('pk', None))
          except Interface.DoesNotExist:
              raise Http404(_('Interface not found.'))
  
          # check permissions on interface (for interface creation)
          self.check_object_permissions(request, self.interface)
  
          # return only interfaces of current interface
          self.queryset = self.model.objects.filter(interface_id=self.interface.id)\
                          .accessible_to(self.request.user)
docs: Custom initial method:
              * ensure interface exists and store it in an instance attribute
              * change queryset to return only devices of current node