Append a null into a list in python
<p>If I have a list:</p>

<pre><code>ex_list = [x,y,z]
</code></pre>

<p>but I want to have</p>

<pre><code>[x, y, z, ]
</code></pre>

<p>How do I do it? I tried:</p>

<pre><code>ex_list.append(None) 
</code></pre>

<p>but that doesn't work.</p>