human
Solve the following python programming problem given the following code:
@ classmethod 
def PushNotification(cls, client, user_id, alert, badge, callback, exclude_device_id = None, extra = None, sound = None) : 
    "Queries all devices for 'user'. Devices with 'push_token'
    set are pushed notifications via the push_notification API.
    NOTE: currently, code path is synchronous, but the callback
      is provided in case that changes.

    If specified, 'exclude_device_id' will exclude a particular device
    from the set to which notifications are pushed. For example, the
    device which is querying notifications when the badge is set to 0.
    " 
    def _OnQuery(devices) : 
        with util.Barrier (callback) as b : 
            now = util.GetCurrentTimestamp () 
            for device in devices : 
                if (device.device_id != exclude_device_id) : 
                    token = device.push_token 
                    assert token, device 
                    try : 
                        PushNotification.Push (token, alert = alert, badge = badge, sound = sound, extra = extra) 
except TypeError as e : 
                        logging.error ('bad push token %s', token) 
                        Device._HandleBadPushToken (client, token, time.time (), b.Callback ()) 
except Exception as e : 
                        logging.warning ('failed to push notification to user %d: %s', user_id, e) 
                        raise 
Device.QueryAlertable (client, badge, _OnQuery) 

    
    

    Fix the buggy line: Device.QueryAlertable (client, badge, _OnQuery)
assistant
#Here is Python code to fix the buggy line: Device.

Device.QueryAlertable (client, user_id, _OnQuery)