Append HTML to an LI of wp_list_categories

Im currently using <?php wp_list_categories('child_of=4&title_li='); ?> to echo out a list of my categories. I’m wondering how I could append some html (specifically an » to the end of each LI within the link.

See this screenshot for an example of what I’m trying to do:

http://nikibrown.com/uploads/4662272c3f00c669b17952c10d21901c.png

I think this is the cleanest and WordPressiest way to do it:

<?php
$menu_args = array(
    'child_of' => '4',
    'title_li' => '',
    'link_after' => '&raquo;',
);
wp_list_categories($menu_args);
?>