presto-geospatial/src/main/java/io/prestosql/plugin/geospatial/GeoFunctions.java/GeoFunctions/stGeometryN
class GeoFunctions:    @SqlNullable
    @Description("Returns the geometry element at the specified index (indices started with 1)")
    @ScalarFunction("ST_GeometryN")
    @SqlType(GEOMETRY_TYPE_NAME)
    public static Slice stGeometryN(@SqlType(GEOMETRY_TYPE_NAME) Slice input, @SqlType(INTEGER) long index)
    {
        OGCGeometry geometry = deserialize(input);
        if (geometry.isEmpty()) {
            return null;
        }
        GeometryType type = GeometryType.getForEsriGeometryType(geometry.geometryType());
        if (!type.isMultitype()) {
            if (index == 1) {
                return input;
            }
            return null;
        }
        OGCGeometryCollection geometryCollection = ((OGCGeometryCollection) geometry);
        if (index < 1 || index > geometryCollection.numGeometries()) {
            return null;
        }
        OGCGeometry ogcGeometry = geometryCollection.geometryN((int) index - 1);
        return serialize(ogcGeometry);
    }