How To Setup Flask-Login

import datetimefrom flask import Flask, abort, redirect, url_for, requestfrom flask_login import LoginManager, UserMixin, AnonymousUserMixin, current_user, login_required, login_user, logout_userapp = Flask(__name__)app.config.update(    DEBUG = True,    SECRET_KEY = 'xxx',    # conigure login_user(remember=True) valid for 7days, default=1year    REMEMBER_COOKIE_DURATION = datetime.timedelta(days=7))login_manager = LoginManager()login_manager.init_app(app)# show this view on @login_required page if user not loginlogin_manager.login_view = "login"# mock database of usersusers = [    {'id': '1', 'username': 'admin', 'password': 'xxx', 'is_admin': True},    {'id': '2', 'username': 'desmond', 'password': 'yyy', 'is_admin': False}]def find_user_by_id(user_id):    for _user in users:        if _user['id'] == user_id:            return _user    return Nonedef find_user_by_username(username):    for _user in users:        if _user['username'] == username:            return _user    return None# create your custom user classclass LoginUser(UserMixin):    def __init__(self, id):        self.id = id    @property    def username(self):        user = self.get_user()        return user['username']    @property    def is_admin(self):        user = self.get_user()        return user['is_admin']    def get_user(self):        return find_user_by_id(self.id)class AnonymousUser(AnonymousUserMixin):    @property    def username(self):        return None    @property    def is_admin(self):        return None    def get_user(self):        return Nonelogin_manager.anonymous_user = AnonymousUser# load user from session@login_manager.user_loaderdef load_user(user_id):    # you can choose to perform authentication here,    # or overwrite `is_authenticated` for `LoginUser`    user = find_user_by_id(user_id)    if not user:        return None    return LoginUser(id=user_id)

@app.route('/')def home():    if not current_user.is_authenticated:        return 'Please <a href="{0}">login</a>. Test <a href="{1}">private</a>.'.format(url_for('login'), url_for('private'))    return url_for('private')@app.route("/login", methods=["GET", "POST"])def login():    message = "Login"    if request.method == 'POST':        username = request.form['username']        password = request.form['password']        user = find_user_by_username(username)        if user:            if user['password'] == password:                # remeber=True, user remain login after browser closed                login_user(LoginUser(user['id']))                next = request.args.get("next")                if not next:                    next = url_for('private')                return redirect(next)        message = "Login FAIL"    return '''    <p>{0}</p>    <form action="" method="post">        <input type="text" name="username" placeholder="username">        <input type="password" name="password" placeholder="password">        <input type="submit" value="Login">    </form>    '''.format(message)@app.route("/logout")@login_requireddef logout():    logout_user()    return 'Logout OK, <a href="{0}">home</a>'.format(url_for('home'))@app.route("/private")@login_requireddef private():    return 'username={0}, is_admin={1}, <a href="{2}">logout</a>'.format(current_user.username, current_user.is_admin, url_for('logout'))