get_term_children 源码的疑问：if ( $term_id == $child )　自己会是自己的子项？

* @param string $term_id ID of Term to get children.
* @param string $taxonomy Taxonomy Name.
* @return array|WP_Error List of Term IDs. WP_Error returned if `$taxonomy` does not exist.
*/
function get_term_children( $term_id, $taxonomy ) {
if ( ! taxonomy_exists($taxonomy) )
return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));

$term_id = intval( $term_id );

$terms = _get_term_hierarchy($taxonomy);

if ( ! isset($terms[$term_id]) )
return array();

$children = $terms[$term_id];

foreach ( (array) $terms[$term_id] as $child ) {
if ( $term_id == $child ) {//　自己会是自己的子项？这种假设没有必要吧？请教达人
continue;
}

if ( isset($terms[$child]) )
$children = array_merge($children, get_term_children($child, $taxonomy));
}

return $children;
}