code: public Map<String, String> getFlattened() {
      final TreeMap<String, String> returnVal = new TreeMap<>();
      returnVal.putAll(getMapByPrefix(""));
      return returnVal;
    }
docs: Returns a new constructed map of all the flattened properties, the item in the returned
  map is sorted alphabetically by the key value.
  
  @Return a new constructed TreeMap (sorted map) of all properties (including parents'
  properties)