Raspberry pi fan control

#!/usr/bin/env python3
# Author: Edoardo Paolo Scalafiotti <edoardo849@gmail.com>
import os
from time import sleep
import signal
import sys
import RPi.GPIO as GPIO

pin = 12  # The pin ID, edit here to change it
maxTMP = 55  # The maximum temperature in Celsius after which we trigger the fan
fan_off_on = 45

def setup():
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(pin, GPIO.OUT)
    GPIO.setwarnings(False)
    return ()


def getCPUtemperature():
    #res = os.popen('/opt/vc/bin/vcgencmd measure_temp').readline()
    res = os.popen('cat /sys/class/thermal/thermal_zone0/temp').readline()
    #temp = (res.replace("temp=", "").replace("'C\n", ""))
    temp = (int(res.replace("\n", "")) / 1000)
    #print(f"Temperature: {temp}")
    return temp


def fanON():
    #print('ON')
    setPin(True)
    return ()


def fanOFF():
    #print('OFF')
    setPin(False)
    return ()


def getTEMP():
    CPU_temp = float(getCPUtemperature())
    if CPU_temp > maxTMP:
        fanON()
    elif CPU_temp < fan_off_on:
        fanOFF()
    return ()


def setPin(mode):  # A little redundant function but useful if you want to add logging
    GPIO.output(pin, mode)
    return ()


try:
    setup()
    while True:
        getTEMP()
        sleep(5)  # Read the temperature every 5 sec, increase or decrease this limit if you want
except KeyboardInterrupt:  # trap a CTRL+C keyboard interrupt
    GPIO.cleanup()  # resets all GPIO ports used by this program
    
# And after, you need add to the crontab a next string
# @reboot python /usr/local/bin/fan_control