feed rewrite

static function conocimiento_comun_rewrite( $wp_rewrite )
{
    $feed_name = "conocimiento_comun";
    $feed_rules = array(
        "feed/$feed_name/(.*)" => "index.php?feed=$feed_name&parent_id=" . $wp_rewrite->preg_index(1),
    );

    $wp_rewrite->rules = $feed_rules + $wp_rewrite->rules;
}