def blink():
    import machine, time

    print("blink")

    pin = machine.Pin(2, machine.Pin.OUT)

    while True:
        pin.value(not pin.value())
        time.sleep_ms(500)

def distance(trigger, echo):
    from hcsr04 import HCSR04
    import time

    sensor = HCSR04(trigger_pin=trigger, echo_pin=echo)

    while True:
        print(sensor.distance_cm())
        time.sleep(1)