Specifically arranged by him as Shchedryk. It sounds like the tune, especially the ostinato predates that by quite a bit.

The chant based on an ostinato four-note pattern within the range of a minor third is thought to be of prehistoric origins and was associated with the coming New Year which in Ukraine before the introduction of Christianity was originally celebrated in April.

https://en.m.wikipedia.org/wiki/Shchedryk_(song)