What exactly is contained within a obj.__closure__?
<p>Beazley pg 100 mentions:</p>

<pre><code>&gt;&gt;&gt;python.__closure__
(&lt;cell at 0x67f50: str object at 0x69230&gt;,)
&gt;&gt;&gt;python.__closure__[0].cell_contents
</code></pre>

<p>my understanding is that <code>__closure__</code> is a list but what's all this
cell stuff and str object?? That looks like a 1-ary tuple?</p>
