import time
time.sleep(0.1) # Wait for USB to become ready
from machine import Pin 
ledr=Pin(2,Pin.OUT) 
ledg=Pin(3,Pin.OUT) 
ledb=Pin(4,Pin.OUT) 

for x in range(10):
    ledr.on() 
    time.sleep(1)
    ledr.off() 
    ledg.on() 
    time.sleep(1)
    ledg.off() 
    ledb.on() 
    time.sleep(1)
    ledb.off()