code: public Observable<ServiceResponse<Page<CertificateItem>>> getCertificatesSinglePageAsync(final String vaultBaseUrl, final Integer maxresults) {
          if (vaultBaseUrl == null) {
              throw new IllegalArgumentException("Parameter vaultBaseUrl is required and cannot be null.");
          }
          if (this.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.apiVersion() is required and cannot be null.");
          }
          String parameterizedHost = Joiner.on(", ").join("{vaultBaseUrl}", vaultBaseUrl);
          return service.getCertificates(maxresults, this.apiVersion(), this.acceptLanguage(), parameterizedHost, this.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<Page<CertificateItem>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<CertificateItem>>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<PageImpl<CertificateItem>> result = getCertificatesDelegate(response);
                          return Observable.just(new ServiceResponse<Page<CertificateItem>>(result.body(), result.response()));
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: List certificates in a specified key vault.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param maxresults Maximum number of results to return in a page. If not specified the service will return up to 25 results.
  @return the PagedList&lt;CertificateItem&gt; object wrapped in {@link ServiceResponse} if successful.