code: public OperationFuture<Server> removePublicIp(Server serverRef, String ipAddress) {
          checkNotNull(ipAddress, "ipAddress must be not null");
  
          Link response = client.removePublicIp(idByRef(serverRef), ipAddress);
  
          return new OperationFuture<>(
              serverRef,
              response.getId(),
              queueClient
          );
      }
docs: Remove public IP from server
  
  @param serverRef server reference
  @param ipAddress  existing public IP address
  @return OperationFuture wrapper for ServerRef