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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def start():
    '''
    Start the saltnado!
    '''
    mod_opts = __opts__.get(__virtualname__, {})

    if 'num_processes' not in mod_opts:
        mod_opts['num_processes'] = 1

    if mod_opts['num_processes'] > 1 and mod_opts.get('debug', False) is True:
        raise Exception((
            'Tornado\'s debug implementation is not compatible with multiprocess. '
            'Either disable debug, or set num_processes to 1.'
        ))

    # the kwargs for the HTTPServer
    kwargs = {}
    if not mod_opts.get('disable_ssl', False):
        if 'ssl_crt' not in mod_opts:
            log.error("Not starting '%s'. Options 'ssl_crt' and "
                    "'ssl_key' are required if SSL is not disabled.",
                    __name__)

            return None
        # cert is required, key may be optional
        # https://docs.python.org/2/library/ssl.html#ssl.wrap_socket
        ssl_opts = {'certfile': mod_opts['ssl_crt']}
        if mod_opts.get('ssl_key', False):
            ssl_opts.update({'keyfile': mod_opts['ssl_key']})
        kwargs['ssl_options'] = ssl_opts

    import tornado.httpserver
    http_server = tornado.httpserver.HTTPServer(get_application(__opts__), **kwargs)
    try:
        http_server.bind(mod_opts['port'],
                         address=mod_opts.get('address'),
                         backlog=mod_opts.get('backlog', 128),
                         )
        http_server.start(mod_opts['num_processes'])
    except Exception:
        log.error('Rest_tornado unable to bind to port %s', mod_opts['port'], exc_info=True)
        raise SystemExit(1)

    try:
        tornado.ioloop.IOLoop.current().start()
    except KeyboardInterrupt:
        raise SystemExit(0)