How to kill a process using Python

constants.py

PID_FILE = 'pid.txt'

kill.py

import os
from constants import PID_FILE

if not os.path.exists(PID_FILE):
    exit('nothing to kill')

pid = int(open(PID_FILE).read())

print("killing by pid: %d" % pid)

if os.name == 'nt':
    os.system("taskkill /pid %d" % pid)
else:
    os.kill(pid, signal.SIGKILL)

os.remove(PID_FILE)

sample-service.py

import os
from time import sleep, strftime
from constants import PID_FILE

open(PID_FILE, 'w').write(str(os.getpid()))

while True:
    sleep(1)
    print(strftime("%H:%M:%S"))