@Override
    public int hashCode() {
        int ret = super.hashCode();
        for (ExpressionNode node : args) {
            ret += node.hashCode();
        }
        return ret;
    }
<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