title: Why does [].append() not work in python?
body: <p>Why does this work - </p>
  
  <pre><code>a = []
  a.append(4)
  print a
  </code></pre>
  
  <p>But this does not - </p>
  
  <pre><code>print [].append(4)
  </code></pre>
  
  <p>The output in second case is <code>None</code>. Can you explain the output?</p>