/**
  * Save meta value
  * If field is cloneable, value is saved as a single entry in DB
  * Otherwise value is saved as multiple entries (for backward compatibility)
  *
  * @param $new
  * @param $old
  * @param $post_id
  * @param $field
  *
  * @return void
  */
 static function save($new, $old, $post_id, $field)
 {
     if (!$field['clone']) {
         parent::save($new, $old, $post_id, $field);
         return;
     }
     if (empty($new)) {
         delete_post_meta($post_id, $field['id']);
     } else {
         update_post_meta($post_id, $field['id'], $new);
     }
 }