Taking the union of sets
<p>I have a list <code>l</code> of sets. To take the union of all the sets in <code>l</code> I do:</p>

<pre><code>union = set()
for x in l:
   union |= x
</code></pre>

<p>I have a feeling there is a more economical/functional way of writing this. Can I improve upon this?</p>
