code: def next_primary_replica_name_for_backup(self, instance_id, master_primary_rank,
                                               primaries, node_reg, node_ids):
          
          if node_reg is None:
              node_reg = self.node.nodeReg
          total_nodes = len(node_reg)
          rank = (master_primary_rank + 1) % total_nodes
          name = self.node.get_name_by_rank(rank, node_reg, node_ids)
          while name in primaries:
              rank = (rank + 1) % total_nodes
              name = self.node.get_name_by_rank(rank, node_reg, node_ids)
          return name, Replica.generateName(nodeName=name, instId=instance_id)
docs: Returns name and corresponding instance name of the next node which
          is supposed to be a new Primary for backup instance in round-robin
          fashion starting from primary of master instance.