this is a script i use:
from rpi_ws281x import PixelStrip
from time import time, sleep, localtime, strftime
from grove.gpio import GPIO
from RPi import GPIO as io
def light_led(led, pix, r, g, b):
for pixel in range(pix):
led.setPixelColorRGB(pixel, r, g, b)
print("led mode {} {} {}".format(str(r),str(g),str(b)))
led.show()
led20 = PixelStrip(16, 12) # Grove RGB led connected to grove PWM
led20.begin()
light_led(led20, 16, 55, 0, 0)
light_led(led20, 16, 55, 0,0)
sleep(5)
light_led(led20, 16, 0, 55, 0)
sleep(5)
led20._cleanup()