code: public OperationFuture<FirewallPolicy> create(FirewallPolicyConfig config) {
          String dataCenterId = dataCenterService.findByRef(config.getDataCenter()).getId();
  
          FirewallPolicyMetadata firewall = firewallPolicyClient.create(
              dataCenterId,
              composeFirewallPolicyRequest(config)
          );
  
          return new OperationFuture<>(
              FirewallPolicy.refById(
                  firewall.getId(),
                  DataCenter.refById(dataCenterId)
              ),
              new NoWaitingJobFuture()
          );
      }
docs: Create firewall policy
  
  @param config firewall policy config
  @return OperationFuture wrapper for firewall policy