docs: public String key(String key, Object... args) {
  
          if ((args == null) || (args.length == 0)) {
              // no parameters available, use simple key method
              return key(key);
          }
  
          String result = key(key, true);
          if (result == null) {
              // key was not found
              result = formatUnknownKey(key);
          } else {
              result = formatMessage(result, args);
          }
          // return the result
          return result;
      }