How to use the gevent.event.Event function in gevent

if sqlalchemy is not None:
        # Set up gevent compatibility in psycopg2
        import psycogreen.gevent
        psycogreen.gevent.patch_psycopg()

    if manhole is not None:
        # Enable manhole for debugging.  Use oneshot mode
        # for gevent compatibility
        manhole.cry = lambda message: log.info("MANHOLE: %s" % message)
        manhole.install(oneshot_on=signal.SIGUSR1)

    m = Manager()
    m.start()

    complete = gevent.event.Event()

    def shutdown():
        log.info("Signal handler: stopping")
        complete.set()

    gevent.signal(signal.SIGTERM, shutdown)
    gevent.signal(signal.SIGINT, shutdown)

    while not complete.is_set():
        complete.wait(timeout=1)

def _get(self):
        if not len(self._data):
            if not self._event:
                self._event = gevent.event.Event()
            self._event.wait()
            return self._get()
        return self._data.pop(0)

def start_transfers(idx, curr_asset, num_transfers):
        curr_app = apps[idx]
        asset_manager = curr_app.raiden.get_manager_by_asset_address(curr_asset)

        all_paths = asset_manager.channelgraph.get_paths_of_length(
            source=curr_app.raiden.address,
            num_hops=2,
        )
        path = all_paths[0]
        target = path[-1]

        finished = gevent.event.Event()

        def _transfer():
            api = curr_app.raiden.api
            for i in range(num_transfers):
                async_result = api.transfer_async(curr_asset, amount, target)
                async_result.wait()

            finished.set()

        gevent.spawn(_transfer)
        return finished

def start(self, timeout):
        """Start the backend and wait until it is initialized."""
        self._startup_pipe = os.pipe()
        pid = os.fork()
        if pid == 0:
            # child
            self.main()
            os._exit(0)
        # parent
        self.backend = pid
        self.listener.close()
        os.close(self._startup_pipe[1])
        self._sigchld_event = Event()
        event = get_hub().loop.signal(signal.SIGCHLD)
        event.start(self._signal_handler, signal.SIGCHLD)
        self.logger.debug('forked backend process, pid = %s', pid)
        self.logger.debug('waiting for it to initialize')
        status = self._get_startup_status(timeout)
        self.logger.debug('initialization status = %s', status)
        if not status:
            self.logger.debug('backend failed to start up after %d seconds', timeout)
            self.error_name = 'Timeout'
            self.error_message = 'A timeout occurred'
            self.error_detail = 'Backend failed to start up after %d seconds' % timeout
        elif status and status.startswith('ERROR:'):
            p1 = status.find(':')
            p2 = status.find(':', p1+1)
            p3 = status.find(':', p2+1)
            self.error_name = status[p1+1:p2]

self.jobs = OrderedDict()
        self.verbose = verbose

        # Keeps track of resource usage
        self.resources = {
                # TODO: break this into CPU cores, memory usage, IO usage, etc.
                'parse_folder_task_pool': [Resource()],
                'create_db_task_pool': [Resource(max_value=2)],
                'analyze_db_task_pool': [Resource(max_value=4)],
                'inference_task_pool': [Resource(max_value=4)],
                'gpus': [Resource(identifier=index)
                    for index in gpu_list.split(',')] if gpu_list else [],
                }

        self.running = False
        self.shutdown = gevent.event.Event()

def __init__(self):
        super(ProcessMonitorThread, self).__init__()
        self._complete = gevent.event.Event()

        self._socket = None

def __init__(self, client, config):
        self.client = client
        self.config = config

        self.ready = Event()
        self.guilds_waiting_sync = 0

        self.me = None
        self.dms = HashMap()
        self.guilds = HashMap()
        self.channels = HashMap(weakref.WeakValueDictionary())
        self.users = HashMap(weakref.WeakValueDictionary())
        self.voice_clients = HashMap(weakref.WeakValueDictionary())
        self.voice_states = HashMap(weakref.WeakValueDictionary())

        # If message tracking is enabled, listen to those events
        if self.config.track_messages:
            self.messages = DefaultHashMap(lambda: deque(maxlen=self.config.track_messages_size))
            self.EVENTS += ['MessageDelete', 'MessageDeleteBulk']

        # The bound listener objects

def __init__(self, config, msg_reader, datastore_writer, hosts_ipset):
        super(DatastoreReader, self).__init__()
        self._config = config
        self.hosts_ipset = hosts_ipset
        self._msg_reader = msg_reader
        self._datastore_writer = datastore_writer
        # Whether we've been in sync with etcd at some point.
        self._been_in_sync = False
        # Keep track of the config loaded from etcd so we can spot if it
        # changes.
        self.last_global_config = None
        self.last_host_config = None
        # Events triggered by the DatastoreAPI Actor to tell us to load the
        # config and start polling.  These are one-way flags.
        self.load_config = Event()
        self.begin_polling = Event()
        # Event that we trigger once the config is loaded.
        self.configured = Event()
        # Polling state initialized at poll start time.
        self.splitter = None
        # Next-hop IP addresses of our hosts, if populated in etcd.
        self.ipv4_by_hostname = {}
        # Forces a resync after the current poll if set.  Safe to set from
        # another thread.  Automatically reset to False after the resync is
        # triggered.
        self.resync_requested = False
        # True if we've been shut down.
        self.killed = False
        # Stats.
        self.read_count = 0
        self.ip_upd_count = 0

def __init__(self):
        self._data = []
        self._event = gevent.event.Event()