Why do Python lists have an extend method?
<p>What does <code>a_list.extend(list2)</code> do (or do better) that <code>a_list += list2</code> doesn't? </p>

<p>That's all really, except to observe that it would have been an answer if <code>.extend()</code> returned the extended list so you could cascade another method. But it doesn't, so you can't.</p>