@Override
    public InterpolatedLookup copy() {
        return new InterpolatedLookup(getLabel(), getLevelOrNull(), getAttributeName(), getLookupArgument().copy());
    }
Constructs a new instance of this class.

@param attributeName the attribute name to assign to this.
@param lookupArgument Expression giving a floating-point value for the lookup argument
container-search/src/main/java/com/yahoo/search/grouping/request/InterpolatedLookup.java