title: Django - unsupported format character 'a' (0x61)
body: <p>I was receiving the following error </p>
  
  <pre><code>unsupported format character 'a' (0x61) at index 16
  
  def send_notification_email(sender, **kwargs):
      change = sender
      print "=========================================="
      mail_admins(subject="model %(model) has been changed by %(user)" % 
                              {'model':change.content_type, 'user': change.user},
                  message = render_to_string('change_email.html', { 'change': change }) )
  </code></pre>
  
  <p>Any suggestions?</p>