code: def _setup_last_ordered_for_non_master(self):
          
          if not self.isMaster and self.first_batch_after_catchup and \
                  not self.isPrimary:
              # If not master instance choose last ordered seq no to be 1 less
              # the lowest prepared certificate in this view
              lowest_prepared = self.get_lowest_probable_prepared_certificate_in_view(
                  self.viewNo)
              if lowest_prepared is not None:
                  # now after catch up we have in last_ordered_3pc[1] value 0
                  # it value should change last_ordered_3pc to lowest_prepared - 1
                  self.logger.info('{} Setting last ordered for non-master as {}'.
                                   format(self, self.last_ordered_3pc))
                  self.last_ordered_3pc = (self.viewNo, lowest_prepared - 1)
                  self.update_watermark_from_3pc()
                  self.first_batch_after_catchup = False
docs: Since last ordered view_no and pp_seq_no are only communicated for
          master instance, backup instances use this method for restoring
          `last_ordered_3pc`
          :return: