code: public OperationFuture<List<Server>> modifyPublicIp(List<Server> servers, ModifyPublicIpConfig config) {
          List<JobFuture> futures = servers.stream()
              .map(serverRef -> modifyPublicIp(serverRef, config).jobFuture())
              .collect(toList());
  
          return new OperationFuture<>(
              servers,
              new ParallelJobsFuture(futures)
          );
      }
docs: Modify ALL existing public IPs on servers
  @param servers The list of server references
  @param config  publicIp config
  @return OperationFuture wrapper for list of ServerRef