[Django]-Django CMS page_attribute falls back to other values?

I’ve just given this a go & you can conditionally override the block like so;

{% extends 'base.html' %}

{% load i18n cms_tags %}
{% page_attribute "page_title" as cms_title %}

{% if cms_title %}
    {% block title %}
        {{ cms_title }}
    {% endblock %}
{% endif %}