code: public static CmsUUID readId(JSONObject obj, String key) {
  
          String strValue = obj.optString(key);
          if (!CmsUUID.isValidUUID(strValue)) {
              return null;
          }
          return new CmsUUID(strValue);
      }
docs: Reads a UUID from a JSON object.
  
  Returns null if the JSON value for the given key is not present or not a valid UUID
  
  @param obj the JSON object
  @param key the JSON key
  
  @return the UUID