old_contents: from machine import Pin
  from machine import PWM
  
  def pitch(freq,pwm):
  	pwm.duty(512)
  	pwm.freq(freq)
  def stop(pwm):
  	pwm.duty(512)
  	pwm.freq(20000)
  	pwm.deinit()
new_contents: from machine import Pin
  from machine import PWM
  
  def pitch(freq,pwm):
  	pwm.duty(512)
  	pwm.freq(freq)
  def stop(pwm):
  	pwm.duty(0)
  	pwm.freq(1)
subject: fix some bug