@Override
    public Md5Function copy() {
        return new Md5Function(getLabel(), getLevelOrNull(), getArg(0).copy(), (LongValue)getArg(1).copy());
    }
Constructs a new instance of this class.

@param exp     The expression to evaluate.
@param numBits The number of bits of the md5 to include.
container-search/src/main/java/com/yahoo/search/grouping/request/Md5Function.java