code: public static boolean verifySubset(Config superConfig, Config subConfig) {
      for (Map.Entry<String, ConfigValue> entry : subConfig.entrySet()) {
        if (!superConfig.hasPath(entry.getKey()) || !superConfig.getValue(entry.getKey()).unwrapped()
            .equals(entry.getValue().unwrapped())) {
          return false;
        }
      }
      return true;
    }
docs: Check that every key-value in superConfig is in subConfig