{"_yql_row_spec"={
    "Type"=["StructType";[
        ["key";["DataType";"String"]];
        ["subkey";["DataType";"String"]];
        ["value";["DataType";"String"]];
        ["biguint";["DataType";"Uint64"]];
        ["negint";["DataType";"Int64"]]
    ]];
}}