def METHOD_NAME():
    global response_server
    global response_add_date
    if opt.server == 'bjoern':
        import bjoern
        # Note:
        # Bjoern doesn't provide any additional response headers like Date and Server
        # so we need to provide them manually.
        bjoern_version = [i for i in open('requirements-bjoern.txt', 'r') if re.search('bjoern', i)][0].strip().split('==')
        response_server = '{}/{}'.format(*bjoern_version).title()
        response_add_date = True
        bjoern.run(app, host=opt.host, port=opt.port, reuse_port=True)
    if opt.server == 'fastwsgi':
        import fastwsgi
        response_server = "FastWSGI"
        response_add_date = False
        fastwsgi.server.backlog = 4096
        fastwsgi.run(app, host=opt.host, port=opt.port, loglevel=opt.verbose)
    if opt.server == 'socketify':
        import socketify
        response_server = None
        response_add_date = False
        socketify.WSGI(app).listen(opt.port, lambda config: logging.info(f"Listening on port http://localhost:{opt.port} now\n")).run()