Hi team, We want to know if there is any built-in function to extract the keys in MULTISET <https://ci.apache.org/projects/flink/flink-docs-release-1.13/docs/dev/table/types/> to be an ARRAY. There is no such function as far as we can find, except to define a simple wrapper UDF for that, please advise.
-- *Best wishes,* *- Kai*
