def application(environ, start_response, message=None):
    status = '503 Service Unavailable' 
    output = 'The server is down for scheduled maintainance.\n'
    if message is not None:
        output = output + message

    response_headers = [('Content-type', 'text/plain'),
                        ('Content-Length', str(len(output)))]
    start_response(status, response_headers)

    return [output]