code: public Observable<Void> addAsync(CertificateAddParameter certificate, CertificateAddOptions certificateAddOptions) {
          return addWithServiceResponseAsync(certificate, certificateAddOptions).map(new Func1<ServiceResponseWithHeaders<Void, CertificateAddHeaders>, Void>() {
              @Override
              public Void call(ServiceResponseWithHeaders<Void, CertificateAddHeaders> response) {
                  return response.body();
              }
          });
      }
docs: Adds a certificate to the specified account.
  
  @param certificate The certificate to be added.
  @param certificateAddOptions Additional parameters for the operation
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponseWithHeaders} object if successful.