public function updateInterestGrouping($name, $value, $group_id = false)
    {

        $payload = array(
            'grouping_id' => (FALSE === $group_id) ? $this->grouping_id : $group_id,
            'name' => $name,
            'value' => $value
        );

        $apiCall = 'lists/interest-grouping-update';
        $data = $this->requestMonkey($apiCall, $payload);
        $data = json_decode($data, true);
        if (isset($data['error']))
            throw new MailchimpAPIException($data);
        else
            return true;
    }