Python pyinotify

# coding=utf-8

import os
import sys
import pyinotify

class Monitor(object):
    def __init__(self, path):
        self.path = path

    def run(self):
        handler = EventHandler()
        wm = pyinotify.WatchManager()
        notifier = pyinotify.Notifier(wm, handler)
        wm.add_watch(self.path, pyinotify.IN_MODIFY) # type: ignore
        notifier.loop()

class EventHandler(pyinotify.ProcessEvent):
    def process_IN_MODIFY(self, event):
        print("File '{}' has been modified.".format(event.pathname))

def test_monitor():
    path = '/home/user/demo.txt'
    monitor = Monitor(path)
    pid = os.getpid()
    print("Test running with PID: {}".format(pid))
    print("Monitoring file: {}".format(path))
    monitor.run()

if __name__ == '__main__':
    try:
        path = '/home/user/demo.txt'
        if not os.path.exists(path):
            raise Exception("Path '{}' does not exist.".format(path))
        monitor = Monitor(path)
        monitor.run()
        ### Add testing code
        # print("Starting testing...")
        # test_monitor()
    except Exception as e:
        print(str(e))
        sys.exit(1)