docs: public Observable<BackupLongTermRetentionPolicyInner> listByDatabaseAsync(String resourceGroupName, String serverName, String databaseName) {
          return listByDatabaseWithServiceResponseAsync(resourceGroupName, serverName, databaseName).map(new Func1<ServiceResponse<BackupLongTermRetentionPolicyInner>, BackupLongTermRetentionPolicyInner>() {
              @Override
              public BackupLongTermRetentionPolicyInner call(ServiceResponse<BackupLongTermRetentionPolicyInner> response) {
                  return response.body();
              }
          });
      }