what does this line do flask.g.auth.logged_in? : <p>I was going through this piece of code:-</p>

<pre><code>def decorated_function(*args, **kwargs):
    """ Decorated function, actually does the work. """
    if not flask.g.auth.logged_in:
        flask.flash('Login required', 'errors')
        return flask.redirect(flask.url_for(
            'login_fedora', next=flask.request.url))

    return function(*args, **kwargs)
</code></pre>

<p>but i am not getting what this line <code>if not flask.g.auth.logged_in:</code> does?</p>
