function update_perch_mailchimp($last_update)
{
    $API = new PerchAPI(1.0, 'perch_mailchimp');
    include 'PerchMailchimp_Stats.class.php';
    include 'PerchMailchimp_Stat.class.php';
    $Settings = $API->get('Settings');
    $api_key = $Settings->get('perch_mailchimp_api_key')->settingValue();
    $list_id = $Settings->get('perch_mailchimp_list_id')->settingValue();
    $Stats = new PerchMailchimp_Stats($API);
    if (!$api_key || $api_key == '' || !$list_id || $list_id == '') {
        return array('result' => 'FAILED', 'message' => 'API key or list ID not provided in Settings.');
    } else {
        if ($Stats->populate($api_key, $list_id)) {
            return array('result' => 'OK', 'message' => 'List statistics updated.');
        } else {
            return array('result' => 'WARNING', 'message' => 'Unable to update list statistics.');
        }
    }
}