title: Meaning of leading underscore in list of tuples used to define choice fields?
body: <p>I've seen a few examples defining choice fields like so:</p>
  
  <pre><code>COUNTRIES = (
      ('fr', _('France')),
      ('de', _('Germany')),
      ...
  )
  </code></pre>
  
  <p>(Source: <a href="http://code.djangoproject.com/ticket/5446" rel="noreferrer">http://code.djangoproject.com/ticket/5446</a>
  Also see: <a href="http://djangosnippets.org/snippets/494/" rel="noreferrer">http://djangosnippets.org/snippets/494/</a>)</p>
  
  <p>What is the meaning of the leading underscores? And why is the second value in the tuple even parenthesized?</p>