def _extract_facet_field_name(self, field_label: str, facets: FacetsParameters) -> str:
        """Extract the facet field name from a Vespa field ID."""
        if field_label.startswith(SemiStructuredVespaSchema.FIELD_STRING_ARRAY_PREFIX):
            # strip group:marqo__string_array_ part of name
            return field_label[len(SemiStructuredVespaSchema.FIELD_STRING_ARRAY_PREFIX):]
        # this is only possible if field query was a number without ranges. So group name is n for float and negative n for int
        if not field_label.startswith("marqo__") and not field_label.startswith("predefined(marqo__"):
            if field_label.startswith('neg(') and field_label.endswith(')'):  # neg(n) - when combining
                group_index = field_label[4:-1]
            else:
                group_index = field_label
            if group_index == self._TOTAL_HITS_GROUP_CONST:
                return self._TOTAL_HITS_GROUP_CONST
            group_index = int(group_index)
            return next(iter(facet_field_name for i, facet_field_name in enumerate(facets.fields.keys()) if i == group_index))
            # return facets.fields.items()[group_index][0]
        return field_label.split('{')[1].split('}')[0].strip('"')
Extract the facet field name from a Vespa field ID.
src/marqo/core/semi_structured_vespa_index/semi_structured_vespa_index.py