code: public Observable<ServiceResponse<LongTermRetentionBackupInner>> getWithServiceResponseAsync(String locationName, String longTermRetentionServerName, String longTermRetentionDatabaseName, String backupName) {
          if (locationName == null) {
              throw new IllegalArgumentException("Parameter locationName is required and cannot be null.");
          }
          if (longTermRetentionServerName == null) {
              throw new IllegalArgumentException("Parameter longTermRetentionServerName is required and cannot be null.");
          }
          if (longTermRetentionDatabaseName == null) {
              throw new IllegalArgumentException("Parameter longTermRetentionDatabaseName is required and cannot be null.");
          }
          if (backupName == null) {
              throw new IllegalArgumentException("Parameter backupName is required and cannot be null.");
          }
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          return service.get(locationName, longTermRetentionServerName, longTermRetentionDatabaseName, backupName, this.client.subscriptionId(), this.client.apiVersion(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<LongTermRetentionBackupInner>>>() {
                  @Override
                  public Observable<ServiceResponse<LongTermRetentionBackupInner>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<LongTermRetentionBackupInner> clientResponse = getDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Gets a long term retention backup.
  
  @param locationName The location of the database.
  @param longTermRetentionServerName the String value
  @param longTermRetentionDatabaseName the String value
  @param backupName The backup name.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the LongTermRetentionBackupInner object