docs: def __retrieve_updates(self, timeout=20):
          """
          Retrieves any updates from the Telegram API.
          Registered listeners and applicable message handlers will be notified when a new message arrives.
          :raises ApiException when a call has failed.
          """
          if self.skip_pending:
              logger.debug('Skipped {0} pending messages'.format(self.__skip_updates()))
              self.skip_pending = False
          updates = self.get_updates(offset=(self.last_update_id + 1), timeout=timeout)
          self.process_new_updates(updates)