human
Solve the following python programming problem given the following code:
@ defer.inlineCallbacks 
def _background_reindex_origin_server_ts(self, progress, batch_size) : 
    target_min_stream_id = progress ['target_min_stream_id_inclusive'] 
    max_stream_id = progress ['max_stream_id_exclusive'] 
    rows_inserted = progress.get ('rows_inserted', 0) 
    INSERT_CLUMP_SIZE = 1000 
    def reindex_search_txn(txn) : 
        sql = 'SELECT stream_ordering, event_id FROM events WHERE ? <= stream_ordering AND stream_ordering < ? ORDER BY stream_ordering DESC LIMIT ?' 
        txn.execute (sql, (target_min_stream_id, max_stream_id, batch_size)) 
        rows = txn.fetchall () 
        if (not rows) : 
            return 0 
min_stream_id = rows [(- 1)] [0] 
        event_ids = [row [1] for row in rows] 
        events = self._get_events_txn (txn, event_ids) 
        rows = [] 
        for event in events : 
            try : 
                event_id = event.event_id 
                origin_server_ts = event.origin_server_ts 
except (KeyError, AttributeError) : 
                continue 
rows.append ((origin_server_ts, event_id)) 
sql = 'UPDATE events SET origin_server_ts = ? WHERE event_id = ?' 
        for index in range (0, len (rows), INSERT_CLUMP_SIZE) : 
            clump = rows [index : (index + INSERT_CLUMP_SIZE)] 
            txn.executemany (sql, clump) 
progress = { 
            'target_min_stream_id_inclusive' : target_min_stream_id, 
            'max_stream_id_exclusive' : min_stream_id, 
            'rows_inserted' : (rows_inserted + len (rows)), 
} 
        self._background_update_progress_txn (txn, self.EVENT_ORIGIN_SERVER_TS_NAME, progress) 
        return len (rows) 
result = (yield self.runInteraction (self.EVENT_ORIGIN_SERVER_TS_NAME, <MASK>)) 
    if (not result) : 
        (yield self._end_background_update (self.EVENT_ORIGIN_SERVER_TS_NAME)) 
defer.returnValue (result) 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: INSERT_CLUMP_SIZE, self, batch_size, rows_inserted, result, target_min_stream_id, progress, max_stream_id
assistant
#Here is a proper replacement for <MASK>.
def reindex_search_txn(