def filter_queryset(self, queryset):
    for backend in set((set(self.filter_backends) | set((self.extra_filter_backends or [])))):
        queryset = backend().filter_queryset(self.request, queryset, self)
    return queryset
def filter_queryset(self, queryset):
    for backend in set((set(self.filter_backends) | set((self.extra_filter_backends or [])))):
        queryset = backend().filter_queryset(self.request, queryset, self)
    return queryset