Toggle a cooling fan on and off to keep the Raspberry Pi between 70 and 75C

cooling.py

#!/usr/bin/env python3

import sys
import os
import time
import vcgencmd as vc
from gpiozero import OutputDevice

def main():
    fan = OutputDevice(18)
    while True:
        temp = int(vc.measure_temp())
        print(temp)
        if  temp >= 75:
            fan.on()
            print("fan.on()")
        elif temp <= 70:
            fan.off()
            print("fan.off()")
        time.sleep(1)

if __name__ == '__main__':
    main()

Traceback (most recent call last):
File "cooling.py", line 6, in
import vcgencmd as vc
ImportError: No module named vcgencmd

you need to install
https://github.com/nicmcd/vcgencmd
test it like this

from vcgencmd import Vcgencmd

vcgm = Vcgencmd()
output = vcgm.measure_temp()
print(output)

remember to run as root if not you will nto have access to GIO in the test