docs: private String lookupAttributeName(String attribute) {
      // .toLowerCase() because the original methods were not camel cased.
      String result = attribute.toLowerCase();
      String tmp;
  
      if (this.tokenAttributesMap != null) {
        tmp = this.tokenAttributesMap.get(attribute);
        result = (tmp == null) ? result : tmp;
      }
  
      return result;
    }