What is the usage of else: after a try/except clause
<blockquote>
  <p><strong>Possible Duplicates:</strong><br>
  <a href="http://stackoverflow.com/questions/1316002/when-is-it-necessary-to-add-an-else-clause-to-a-try-except-in-python">when is it necessary to add an <code>else</code> clause to a try..except in Python?</a><br>
  <a href="http://stackoverflow.com/questions/855759/python-try-else">Python try-else</a>  </p>
</blockquote>



<pre><code>for arg in sys.argv[1:]:
    try:
        f = open(arg, 'r')
    except IOError:
        print 'cannot open', arg
    else:
        print arg, 'has', len(f.readlines()), 'lines'
        f.close()
</code></pre>

<p>What is usage of this else clause, and when will it be executed? </p>
