Django Invalid block tag: 'else'

问题

Newbie question.

I need to extend to the user template if the user is authenticated otherwise extend the guest template.

I have the following code at the top my page.

{% if request.user.is_authenticated %}
    {% extends 'users/base.html' %}
{% else %}
    {% extends 'guests/base.html' %}
{% endif %}

But then I get the following error:

TemplateSyntaxError at /events/
Invalid block tag: 'else'

If I don't use extends inside the condition then it works. So i'm confuse what is wrong:

{% if request.user.is_authenticated %}
    user
{% else %}
    guest
{% endif %}

来源：https://stackoverflow.com/questions/23789434/django-invalid-block-tag-else