code qui fonctionne pas pour les loosers du milieu

import music
import radio
import neopixel
from microbit import *


radio.on()
radio.config(channel=68,power=7)
alerte=False
nb=0
np = neopixel.NeoPixel(pin1,300)
mode=0

while True:
    if button_a.was_pressed():
        radio.send('ALERTE-0')
        display.show(0)
        alerte=True
    if button_b.was_pressed():
        radio.send('STOP-0')
        alerte=False
    message=radio.receive()
    if message is not None:
        message2=message[:-2]
        nb=int(message[-1])
        if message2.lower() is 'stop' and alerte is True and nb<=9:
            radio.send('STOP-'+str(nb+1))
            alerte=False
        elif message2.lower() is 'alerte' and alerte is False and nb<=9:
            radio.send('ALERTE-'+str(nb+1))
            alerte=True
            display.show(nb+1)
    if mode==0:
        if alerte is True:
            music.pitch(500) 
        else:
            music.stop()
            display.clear()
    else:
        if alerte is True:
            music.pitch(500)
            display.show(nb+1)
            pin2.write_digital(1)
            for pixel_id in range(0, len(np)):
                np[pixel_id] = (0,0,255) #RGB pour le petit et GBR pour le tableau
                np.show()    
        else:
            music.stop()
            display.clear()
            pin2.write_digital(0)
            for pixel_id in range(0, len(np)):
                np[pixel_id] = (0,0,0)
                np.show()