protected function _renderMessages(array $messages)
    {
        // Don't create list for single message
        if (count($messages) == 1) {
            return reset($messages);
        }

        // Start output
        $output = '<ul>';

        // Loop through messages
        foreach ($messages as $message) {

            // Add message
            $output .= '<li>' . $message . '</li>';
        }

        // Finish output
        $output .= '</ul>';

        return $output;
    }