missing documentation for mailchimp_subscribe()/mailchimp_unsubscribe()

/**
 * Subscribe a user to a MailChimp list in real time or by adding to the queue.
 *
 * @see Mailchimp_Lists::subscribe()
 */
function mailchimp_subscribe($list_id, $email, $merge_vars = NULL, $interests = array(), $double_optin = FALSE, $format = 'html') {

...

/**
 * Unsubscribes a member from a MailChimp list.
 *
 * @see Mailchimp_Lists::unsubscribe()
 */
function mailchimp_unsubscribe($list_id, $email, $delete = FALSE, $goodbye = FALSE, $notify = FALSE) {

However, the MailchimpLists class in the Mailchimp API has no such methods.