code: public Observable<ServiceResponse<Page<DeletedSecretItem>>> getDeletedSecretsNextSinglePageAsync(final String nextPageLink) {
          if (nextPageLink == null) {
              throw new IllegalArgumentException("Parameter nextPageLink is required and cannot be null.");
          }
          String nextUrl = String.format("%s", nextPageLink);
          return service.getDeletedSecretsNext(nextUrl, this.acceptLanguage(), this.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<Page<DeletedSecretItem>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<DeletedSecretItem>>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<PageImpl<DeletedSecretItem>> result = getDeletedSecretsNextDelegate(response);
                          return Observable.just(new ServiceResponse<Page<DeletedSecretItem>>(result.body(), result.response()));
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Lists deleted secrets for the specified vault.
  The Get Deleted Secrets operation returns the secrets that have been deleted for a vault enabled for soft-delete. This operation requires the secrets/list permission.
  
  @param nextPageLink The NextLink from the previous successful call to List operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the PagedList&lt;DeletedSecretItem&gt; object wrapped in {@link ServiceResponse} if successful.