code: public Observable<DeletedCertificateBundle> deleteCertificateAsync(String vaultBaseUrl, String certificateName) {
          return deleteCertificateWithServiceResponseAsync(vaultBaseUrl, certificateName).map(new Func1<ServiceResponse<DeletedCertificateBundle>, DeletedCertificateBundle>() {
              @Override
              public DeletedCertificateBundle call(ServiceResponse<DeletedCertificateBundle> response) {
                  return response.body();
              }
          });
      }
docs: Deletes a certificate from a specified key vault.
  Deletes all versions of a certificate object along with its associated policy. Delete certificate cannot be used to remove individual versions of a certificate object. This operation requires the certificates/delete 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 observable to the DeletedCertificateBundle object