human
Solve the following python programming problem given the following code:
@ testing.requires.timing_intensive 
def test_recycle_pool_no_race(self) : 
    def slow_close() : 
        slow_closing_connection._slow_close () 
        time.sleep (0.5) 
slow_closing_connection = Mock () 
    slow_closing_connection.connect.return_value.close = slow_close 
    class Error (Exception) : 
        pass 
dialect = Mock () 
    dialect.is_disconnect = (lambda * arg, **kw : True) 
    dialect.dbapi.Error = Error 
    pools = [] 
    class TrackQueuePool (pool.QueuePool) : 
        def __init__(self, * arg, **kw) : 
            pools.append (self) 
            super (TrackQueuePool, self).__init__ (* arg, ** kw) 
def creator() : 
        return slow_closing_connection.connect () 
p1 = TrackQueuePool (creator = creator, pool_size = 20) 
    from sqlalchemy import create_engine 
    eng = create_engine (testing.db.url, pool = p1, _initialize = False) 
    eng.dialect = dialect 
    conns = [eng.connect () for i in range (15)] 
    for conn in conns [3 : 10] : 
        conn.close () 
def attempt(conn) : 
        time.sleep (random.random ()) 
        try : 
            conn._handle_dbapi_exception (Error (), 'statement', { 
                
}, Mock (), Mock ()) 
except tsa.exc.DBAPIError : 
            pass 
threads = [] 
    for conn in conns : 
        t = threading.Thread (target = attempt, args = (threads,)) 
        t.start () 
        threads.append (t) 
for t in threads : 
        t.join () 
for conn in conns : 
        conn.close () 
conns = [eng.connect () for i in range (15)] 
    assert (slow_closing_connection._slow_close.call_count == 15) 
    assert (slow_closing_connection.connect.call_count == 30) 
    assert (len (pools) <= 2), len (pools) 

    
    

    Fix the buggy line: t = threading.Thread (target = attempt, args = (threads,))
assistant
#Here is Python program to fix the buggy line: t = threading.

t = threading.Thread (target = attempt, args = (conn,))