$mailing_list = $list->generateList();
$list_count = count($mailing_list);
if($list_count > 0){
    $thetime = time();
    $list_file = 'list_' . $thetime . '.csv';
    $list_file_url = 'lists/' . $list_file;
    $handle = fopen($list_file_url, 'w');
    foreach($mailing_list as $line){
        fwrite($handle, implode(',', $line) ."\n");
    }
fclose($handle);