title: Why is python deque initialized using the last maxlen items in an iterable?
body: <p>I was learning how to use deque. Here's what I did:</p>
  
  <pre><code>&gt;&gt;&gt; d = deque([1,2,3,4,5,6], maxlen=3)
  </code></pre>
  
  <p>I expected that d would contain [1,2,3]. But instead I got:</p>
  
  <pre><code>&gt;&gt;&gt; d
  deque([4, 5, 6], maxlen=3)
  </code></pre>
  
  <p>Isn't this counterintuitive?</p>