human
Solve the following python programming problem given the following code:
def Transform(self, client, viewpoint, callback) : 
    from activity import Activity 
    from viewpoint import Viewpoint 
    def _OnQuery(followers_activities) : 
        ((follower_ids, last_key), activities) = followers_activities 
        activities = [activity for activity in activities if (activity.name == 'share')] 
        if (len (activities) > 0) : 
            oldest_activity = None 
            for activity in activities : 
                if ((oldest_activity is None) or (activity.timestamp < oldest_activity.timestamp)) : 
                    oldest_activity = activity 
activity.name = 'share_existing' 
oldest_activity.name = 'share_new' 
            act_dict = json.loads (activities [(- 1)].json) 
            act_dict ['follower_ids'] = [f_id for f_id in follower_ids if (f_id != viewpoint.user_id)] 
            oldest_activity.json = json.dumps (act_dict) 
            with util.Barrier (partial (callback, viewpoint)) as b : 
                for activity in activities : 
                    self._LogUpdate (activity) 
                    if Version._mutate_items : 
                        activity.Update (client, b.Callback ()) 
else : 
                        b.Callback () () 
else : 
            callback (viewpoint) 
with util.ArrayBarrier (_OnQuery) as b : 
        Viewpoint.QueryFollowerIds (self, viewpoint.viewpoint_id, b.Callback ()) 
        Activity.RangeQuery (client, viewpoint.viewpoint_id, None, None, None, b.Callback ()) 

    
    

    Fix the buggy line: Viewpoint.QueryFollowerIds (self, viewpoint.viewpoint_id, b.Callback ())
assistant
#Here is Python program to fix the buggy line: Viewpoint.

Viewpoint.QueryFollowerIds (client, viewpoint.viewpoint_id, b.Callback ())