class MTree implements Serializable {

  private void checkStorageGroup(String storageGroup) throws IllegalPathException {
    if (!IoTDBConfig.STORAGE_GROUP_PATTERN.matcher(storageGroup).matches()) {
      throw new IllegalPathException(String
          .format("The storage group name can only be characters, numbers and underscores. %s",
              storageGroup));
    }
  }

    MTree();
  private  MTree(MNode root);

}