title: Convert a number to a list of integers
body: <p>How do I write the <code>magic</code> function below?</p>
  
  <pre><code>&gt;&gt;&gt; num = 123
  &gt;&gt;&gt; lst = magic(num)
  &gt;&gt;&gt;
  &gt;&gt;&gt; print lst, type(lst)
  [1, 2, 3], &lt;type 'list'&gt;
  </code></pre>