@felmue thanx a lot! I use UiFlow1.1 and an example for LED control in python is here:

from m5stack import *
from m5stack_ui import *
from uiflow import *
import i2c_bus
import time

screen = M5Screen()
screen.clean_screen()
screen.set_screen_bg_color(0xFFFFFF)

i2c0 = i2c_bus.easyI2C((21, 22), 0x00, freq=400000)
i2c0.addr=(0x34)
while True:
i2c0.write_u8(0x69, 0x05)
wait(1)
i2c0.write_u8(0x69, 0x35)
wait(1)