python script that toggles DNS blocking when a landline phone is taken on or off the hook (using a Raspberry Pi + door sensor)

phone-hook.py

import RPi.GPIO as GPIO
import time
import subprocess

# input/output setup for the door sensor
GPIO.setmode(GPIO.BOARD)
GPIO.setup(7, GPIO.IN, pull_up_down = GPIO.PUD_UP)

is_off_hook = None
old_off_hook = None

while True:
	old_off_hook = is_off_hook
	is_off_hook = GPIO.input(7)
	
	if (is_off_hook and (is_off_hook != old_off_hook)):
		print("Phone taken off the hook")
		# this script enables DNS blocking by moving a custom configuration file into /etc/dnsmasq.d/
		subprocess.call(['sh', '/path/to/script/block.sh'])
		
	elif (is_off_hook != old_off_hook):
		print("Phone back on the hook")
		# this script turns off DNS blocking by removing the custom configuration file from /etc/dnsmasq.d/
		subprocess.call(['sh', '/path/to/script/unblock.sh'])
		
	else:
		print("No change")
		
	time.sleep(1)