ydb/yql/essentials/tests/s-expressions/suites/Udf/ProtoField.yql

(
#comment
(let mr_source (DataSource 'yt 'plato))
(let x (Read! world mr_source (Key '('table (String 'Input))) '('key 'subkey 'value) '()))
(let world (Left! x))
(let table1 (Right! x))
(let res_sink (DataSink 'result))
(let world (Write! world res_sink (Key) table1 '('('type))))
(let world (Commit! world res_sink))
(return world)
)