code: protected static String getRequiredNameIdFormatIfAny(final RequestAbstractType authnRequest) {
          val nameIDPolicy = getNameIDPolicy(authnRequest);
          val requiredNameFormat = nameIDPolicy != null ? nameIDPolicy.getFormat() : null;
          LOGGER.debug("AuthN request indicates [{}] is the required NameID format", requiredNameFormat);
          return requiredNameFormat;
      }
docs: Gets required name id format if any.
  
  @param authnRequest the authn request
  @return the required name id format if any