问如何删除旧线程并启动新线程？

EN

def led_action(topic,message):
    print topic+" "+message

    if message == 'OFF':
        #state = False
        print ("Stoping...")
        while message == 'OFF':
            GPIO.output(8,GPIO.LOW)

    elif message == 'ON':
        #state = True
        print ("Opening...")
        while message == 'ON':
            GPIO.output(8,GPIO.HIGH)    #Set LED pin 8 to HIGH
            time.sleep(1)           #Delay 1 second
            GPIO.output(8,GPIO.LOW)     #Set LED pin 8 to LOW
            time.sleep(1)

# Get message form NETPIE and Do something 
def subscription(topic,message):
    set = thread.start_new_thread(led_action, (topic,message))

def connection():
    print "Now I am connected with netpie"

def disconnect():
     print "disconnect is work"

microgear.setalias("test")
microgear.on_connect = connection
microgear.on_message = subscription
microgear.on_disconnect = disconnect
microgear.subscribe("/mails")
microgear.connect(True)