presto-geospatial/src/main/java/io/prestosql/plugin/geospatial/GeoFunctions.java/GeoFunctions/stNumInteriorRings
class GeoFunctions:    @SqlNullable
    @Description("Returns the cardinality of the collection of interior rings of a polygon")
    @ScalarFunction("ST_NumInteriorRing")
    @SqlType(BIGINT)
    public static Long stNumInteriorRings(@SqlType(GEOMETRY_TYPE_NAME) Slice input)
    {
        OGCGeometry geometry = deserialize(input);
        validateType("ST_NumInteriorRing", geometry, EnumSet.of(POLYGON));
        if (geometry.isEmpty()) {
            return null;
        }
        return Long.valueOf(((OGCPolygon) geometry).numInteriorRing());
    }