title: Tuple assignment in Python, Is this a bug in Python?
body: <p>I was reading this interesting post <a href="https://asmeurer.github.io/blog/posts/tuples/" rel="noreferrer">https://asmeurer.github.io/blog/posts/tuples/</a></p>
  
  <p>At the footnote author present this example</p>
  
  <pre><code>&gt;&gt;&gt; t=1,2,[3,4]
  &gt;&gt;&gt; t
  (1, 2, [3, 4])
  &gt;&gt;&gt; t[2]+=[5,6]
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  TypeError: 'tuple' object does not support item assignment
  </code></pre>
  
  <p>Although Python has raised a exception but it did change the tuple</p>
  
  <pre><code>&gt;&gt;&gt; t
  (1, 2, [3, 4, 5, 6])
  </code></pre>
  
  <p>Not sure what is going on here, is this a bug?</p>
  
  <p>The behavior is same in 2.7.10 and 3.5.1</p>