static String delimitedStringToListOfString(final String delimiter, final String oldValue) {
        if (oldValue == null || oldValue.isBlank()) {
            return null;
//        } else if (oldValue.isBlank()) {
//            return "";
        } else {
            // Our list serialisation is like '|A|B|C', i.e. prefixed with the delimiter in use
            return delimiter + oldValue;
        }
    }
ModelString e.g. 30d to an ISO-8601 duration string, e.g. P30D
stroom-legacy/stroom-legacy-db-migration/src/main/java/stroom/legacy/db/migration/V07_00_00_1202__property_rename.java