code: public ServiceFuture<List<CertificateItem>> getCertificateVersionsNextAsync(final String nextPageLink, final ServiceFuture<List<CertificateItem>> serviceFuture, final ListOperationCallback<CertificateItem> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              getCertificateVersionsNextSinglePageAsync(nextPageLink),
              new Func1<String, Observable<ServiceResponse<Page<CertificateItem>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<CertificateItem>>> call(String nextPageLink) {
                      return getCertificateVersionsNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: List the versions of a certificate.
  The GetCertificateVersions operation returns the versions of a certificate in the specified key vault. This operation requires the certificates/list permission.
  
  @param nextPageLink The NextLink from the previous successful call to List operation.
  @param serviceFuture the ServiceFuture object tracking the Retrofit calls
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object