@Override
    public LongPredefined copy() {
        return new LongPredefined(getLabel(),
                                  getLevelOrNull(),
                                  getArg(0),
                                  args().stream()
                                        .skip(1)
                                        .map(LongBucket.class::cast)
                                        .map(arg -> arg.copy())
                                        .toList());
    }
Constructs a new instance of this class.

@param exp  The expression to evaluate, must evaluate to a long.
@param arg1 The compulsory bucket.
@param argN The optional buckets.
container-search/src/main/java/com/yahoo/search/grouping/request/LongPredefined.java