protected boolean onCalculate(final List<ExpressionNode> args, ResultNode result) {
        result.set(args.get(0).getResult());
        for (int i = 1; i < args.size(); i++) {
            executeIterative(args.get(i).getResult(), result);
        }
        return true;
    }
<p>Perform the appropriate calculation of the arguments into a result node.</p>

@param args   A list of operands.
@param result Place to put the result.
@return True if successful, false if not.
searchlib/src/main/java/com/yahoo/searchlib/expression/MultiArgFunctionNode.java