I'm ingesting data from S3, which contains dates in epoch format (unix timestamp). I was planning to use the DATE_ADD function to convert this to an actual date, but that only seems to function on a Date attribute with a fixed interval, while I have the opposite situation (fixed date: 1970-01-01, interval attribute, being the epoch time). Does anyone know how I can make this conversion, either in Rules Engine or via a Calculated Field on the object I write the data to?