code: public Observable<ServiceResponse<Void>> purgeDeletedCertificateWithServiceResponseAsync(String vaultBaseUrl, String certificateName) {
          if (vaultBaseUrl == null) {
              throw new IllegalArgumentException("Parameter vaultBaseUrl is required and cannot be null.");
          }
          if (certificateName == null) {
              throw new IllegalArgumentException("Parameter certificateName 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.purgeDeletedCertificate(certificateName, this.apiVersion(), this.acceptLanguage(), parameterizedHost, this.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<Void>>>() {
                  @Override
                  public Observable<ServiceResponse<Void>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<Void> clientResponse = purgeDeletedCertificateDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Permanently deletes the specified deleted certificate.
  The PurgeDeletedCertificate operation performs an irreversible deletion of the specified certificate, without possibility for recovery. The operation is not available if the recovery level does not specify 'Purgeable'. This operation requires the certificate/purge permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param certificateName The name of the certificate
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.