docs: def get_obsolete_user_ids(self, db_read=None):
          """
          Returns obsolete users IDs to unaward.
          """
          db_read = db_read or self.db_read
  
          already_awarded_ids = self.get_already_awarded_user_ids(db_read=db_read, show_log=False)
          current_ids = self.get_current_user_ids(db_read=db_read)
          obsolete_ids = list(set(already_awarded_ids) - set(current_ids))
          obsolete_ids_count = len(obsolete_ids)
  
          logger.debug(
              '→ Badge %s: %d users need to be unawarded',
              self.slug,
              obsolete_ids_count)
  
          return (obsolete_ids, obsolete_ids_count)