@TestOnly
  public boolean createUser(String username, String password, boolean validCheck)
      throws AuthException {
    return createUser(username, password, validCheck, true);
  }
Try to load admin. If it doesn't exist, automatically create one

@throws AuthException if an exception is raised when interacting with the lower storage.
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/auth/user/BasicUserManager.java