title: Why can a dictionary be unpacked as a tuple?
body: <p>Today, I saw one statement which didn't throw an exception. Can anyone explain the theory behind it?</p>
  
  <pre><code>&gt;&gt;&gt; x, y = {'a': 2, 'b': 5}
  &gt;&gt;&gt; x
  'a'
  &gt;&gt;&gt; y
  'b'
  </code></pre>