code: public void purgeDeletedCertificate(String vaultBaseUrl, String certificateName) {
          purgeDeletedCertificateWithServiceResponseAsync(vaultBaseUrl, certificateName).toBlocking().single().body();
      }
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
  @throws KeyVaultErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent