code: private String generateScope(SignableRequest<?> request, String dateStamp,
              String serviceName, String regionName) {
          final StringBuilder scopeBuilder = new StringBuilder();
          return scopeBuilder.append(dateStamp).append("/").append(regionName)
                  .append("/").append(serviceName).append("/")
                  .append(SignerConstants.AWS4_TERMINATOR).toString();
      }
docs: Returns the scope to be used for the signing.