Access channel attribute using MagpieRSS

<?php
$feed = 'http://feeds.feedburner.com/w3mentor?format=rss';
$rss = fetch_rss($feed);
 
print "<ul>\n";
 
foreach ($rss->channel as $key => $value) {
    print "<li>$key: $value</li>\n";
}
 
print "</ul>\n";
?>