does not not_null ever make sense?
<p>I have inherited some code in which the previous coder wrote this:</p>

<pre><code>    if (!not_null($page)) {
       die('&lt;b&gt;Error!&lt;/b&gt;&lt;br&gt;&lt;b&gt;Unable to determine the page link!&lt;br&gt;&lt;br&gt;');
    }
</code></pre>

<p>Is there any advantage to this, as opposed to just saying:
    if (is_null($page))</p>

<p>It seems unnecessarily confusing to me. </p>
