code: protected static Map<String, List<Object>> convertPersonAttributesToPrincipalAttributes(final Map<String, List<Object>> attributes) {
          return attributes.entrySet()
              .stream()
              .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
      }
docs: Convert person attributes to principal attributes.
  
  @param attributes person attributes
  @return principal attributes