user.is_authenticated AttributeError: can't set attribute

In the sample code:

@login_manager.request_loader
def request_loader(request):
    email = request.form.get('email')
    if email not in users:
        return

    user = User()
    user.id = email

    # DO NOT ever store passwords in plaintext and always compare password
    # hashes using constant-time comparison!
    user.is_authenticated = request.form['pw'] == users[email]['pw']

    return user

When username is correct and password is incorrect, get follow error message:

user.is_authenticated = request.form['pw'] == users[email]['pw']
AttributeError: can't set attribute

[davidism]

All users that aren’t anonymous are authenticated, it’s not a property you need to set. Instead, if the passwords don’t match, just don’t return a user object at all.

[PyAntony]

Someone needs to fix that documentation. This is not correct: user.is_authenticated = request.form[‘pw’] == users[email][‘pw’]