def initial(self, request, *args, **kwargs):
        """
        Custom initial method:
            * ensure node exists and store it in an instance attribute
            * change queryset to return only images of current node
        """
        super(NodeImageList, self).initial(request, *args, **kwargs)
        # ensure node exists
        self.node = get_queryset_or_404(
            Node.objects.published().accessible_to(request.user),
            {'slug': self.kwargs['slug']}
        )
        # check permissions on node (for image creation)
        self.check_object_permissions(request, self.node)
Custom initial method:
            * ensure node exists and store it in an instance attribute
            * change queryset to return only images of current node