def _sort_range_facets(self, field_data: Dict) -> Dict:
        """Sort range facets by their upper bound, with None (Infinity) at the end."""
        sorted_items = sorted(field_data.items(), key=lambda kv: kv[1][1])
        return {k: v[0] for k, v in sorted_items}
Sort range facets by their upper bound, with None (Infinity) at the end.
src/marqo/core/semi_structured_vespa_index/semi_structured_vespa_index.py