from machine import Pin, PWM
from time import sleep

buzzer = PWM(Pin(32, Pin.OUT))

def buzz(freq, masa):
    buzzer, freq(freq)
    buzzer, duty(50)
    sleep(masa)

while (True):
    buzz(300, 0.2)
    buzz(350, 0.2)
    buzz(400, 0.2)
    buzz(1, 0.2)