presto-iceberg/src/main/java/io/prestosql/plugin/iceberg/TypeConverter.java/TypeConverter/fromMap
class TypeConverter:    private static org.apache.iceberg.types.Type fromMap(MapType type)
    {
        return Types.MapType.ofOptional(1, 2, toIcebergType(type.getKeyType()), toIcebergType(type.getValueType()));
    }