private function save_custom_fields($level_id, $data)
 {
     $custom_obj = BMembershipLevelCustom::get_instance_by_id($level_id);
     foreach ($data as $item) {
         $custom_obj->set($item);
     }
 }
 public static function get_value_by_context($level_id, $context)
 {
     return BMembershipLevelCustom::get_instance_by_id($level_id)->get_by_context($context);
 }