docs: private static void handleSingletonClass(String key, String value) throws Exception {
          Object object = handleValue(value);
          if(key.contains(",")) {
              String[] interfaces = key.split(",");
              for (String anInterface : interfaces) {
                  serviceMap.put(anInterface, object);
              }
          } else {
              serviceMap.put(key, object);
          }
      }