@Override
    public PredicateQueryItem clone() {
        PredicateQueryItem clone = (PredicateQueryItem)super.clone();
        clone.features = new ArrayList<>(this.features);
        clone.rangeFeatures = new ArrayList<>(this.rangeFeatures);
        return clone;
    }
Returns a mutable collection of range feature entries.
container-search/src/main/java/com/yahoo/prelude/query/PredicateQueryItem.java