presto-geospatial/src/main/java/io/prestosql/plugin/geospatial/GeoFunctions.java/GeoFunctions/stInteriorRings
class GeoFunctions:    @SqlNullable
    @Description("Returns an array of interior rings of a polygon")
    @ScalarFunction("ST_InteriorRings")
    @SqlType("array(" + GEOMETRY_TYPE_NAME + ")")
    public static Block stInteriorRings(@SqlType(GEOMETRY_TYPE_NAME) Slice input)
    {
        OGCGeometry geometry = deserialize(input);
        validateType("ST_InteriorRings", geometry, EnumSet.of(POLYGON));
        if (geometry.isEmpty()) {
            return null;
        }

        OGCPolygon polygon = (OGCPolygon) geometry;
        BlockBuilder blockBuilder = GEOMETRY.createBlockBuilder(null, polygon.numInteriorRing());
        for (int i = 0; i < polygon.numInteriorRing(); i++) {
            GEOMETRY.writeSlice(blockBuilder, serialize(polygon.interiorRingN(i)));
        }
        return blockBuilder.build();
    }