ydb/yql/essentials/tests/s-expressions/suites/ImplictCasts/NullAsOpt.yql

(
(let config (DataSource 'config))
(let world (Configure! world config 'PureDataSource 'yt))

(let res_sink (DataSink 'result))
(let ct (ParseType '"(Uint32?,Uint32)->Uint32"))
(let callable (Callable ct (lambda '(x y) (Coalesce x y))))
(let world (Write! world res_sink (Key) (Apply callable (Null) (Uint32 '2)) '()))
(let world (Commit! world res_sink))
(return world)
)