How to use the @accounts/server.ServerHooks.ValidateLogin function in @accounts/server

}
    return user;
  },
});

const accountsServer = new AccountsServer(
  {
    db: new MongoDBInterface(db),
    tokenSecret: 'secret',
  },
  {
    password: accountsPassword,
  }
);

accountsServer.on(ServerHooks.ValidateLogin, ({ user }) => {
  // This hook is called every time a user try to login.
  // You can use it to only allow users with verified email to login.
  // If you throw an error here it will be returned to the client.
});

app.use(accountsExpress(accountsServer));

app.get('/user', userLoader(accountsServer), (req, res) => {
  res.json({ user: (req as any).user });
});

app.listen(4000, () => {
  console.log('Server listening on port 4000');
});