/**
  * Returns related users for a specific term.
  *
  * Related users of a term are any users which are specified in the registered meta fields of that term (for example in dropdowns).
  * To register a field like that it must use the special key 'users' in the field's options array.
  *
  * @since 0.6.0
  * @param $integer $id the term ID to get related users for
  * @param string $meta_key an optional meta key to only get related users specified as part of that meta key
  * @param string $role an optional user role to only get related users of that role
  * @param boolean $single whether to only return a single user (default is false)
  * @return WP_User|array|null either a WP_User or null (if $single is true) or an array of WP_User objects or empty array otherwise
  */
 function wpptd_get_term_related_users($id, $meta_key = '', $role = '', $single = false)
 {
     return \WPPTD\Utility::get_related_objects('term', $id, 'users', $meta_key, $role, $single);
 }