human
Solve the following python programming problem given the following code:
@ defer.inlineCallbacks 
def get_updated_tags(self, user_id, stream_id) : 
    'Get all the tags for the rooms where the tags have changed since the
        given version

        Args:
            user_id(str): The user to get the tags for.
            stream_id(int): The earliest update to get for the user.
        Returns:
            A deferred dict mapping from room_id strings to lists of tag
            strings for all the rooms that changed since the stream_id token.
        ' 
    def get_updated_tags_txn(txn) : 
        sql = 'SELECT room_id from room_tags_revisions WHERE user_id = ? AND stream_id > ?' 
        txn.execute (sql, (user_id, stream_id)) 
        room_ids = [row [0] for row in txn.fetchall ()] 
        return room_ids 
changed = self._account_data_stream_cache.has_entity_changed (user_id, int (stream_id)) 
    if (not changed) : 
        defer.returnValue ({ 
            
}) 
room_ids = (yield self.runInteraction ('get_updated_tags', <MASK>)) 
    results = { 
        
} 
    if room_ids : 
        tags_by_room = (yield self.get_tags_for_user (user_id)) 
        for room_id in room_ids : 
            results [room_id] = tags_by_room.get (room_id, { 
                
}) 
defer.returnValue (results) 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is a proper replacement for <MASK>.
def get_updated_tags_txn(