code: public Iterator<String> getValues(String inputKey) {
          String key = Normalizer.normalize(inputKey, Normalizer.NORMALIZE_LOWER);
          List<String> vals = this.values.get(key);
          if (null != vals) {
              return vals.iterator();
          }
          return new LinkedList<String>().iterator();
      }
docs: Access an iterator of all values for the target key.
  
  @param inputKey
  @return Iterator (empty list if none present)