/**
 * Writes a common 'unpublish' button.
 *
 * @param   string   $task   An override for the task.
 * @param   string   $alt    An override for the alt text.
 * @param   boolean  $check  True if required to check that a standard list item is checked.
 *
 * @return  void
 *
 * @since   1.5
 */
public static function unpublish($task = 'unpublish', $alt = 'JTOOLBAR_UNPUBLISH', $check = false)
{
    $bar = Toolbar::getInstance('toolbar');
    // Add an unpublish button
    $bar->appendButton('Standard', 'unpublish', $alt, $task, $check);
}