docs: public static List<JSONObject> toList(JSONObject parent, String propertyName) {
          Object v = parent.get(propertyName);
          if(v==null)
              return Collections.emptyList();
          if(v instanceof JSONObject)
              return Collections.singletonList((JSONObject)v);
          if(v instanceof JSONArray)
              return (List)(JSONArray)v;
  
          throw new IllegalArgumentException();
      }