ydb/yql/essentials/tests/s-expressions/suites/GraceJoin/input1opt.txt.attr

{
    "_yql_row_spec" = {
        "Type" = [
            "StructType";
            [
                [
                    "key1";
                    [
                        "OptionalType";
                        [
	                    "DataType";
                            "Int32"
                        ]
                    ]
                ];
                [
                    "subkey1";
                    [
                        "OptionalType";
                        [
	                    "DataType";
                            "String"
                        ]
                    ]
                ];
                [
                    "value1";
                    [
                        "OptionalType";
                        [
	                    "DataType";
                            "String"
                        ]
                    ]
                ]
            ]
        ]
    }
}