How to use the gbulb.unix_events.AbstractChildWatcher function in gbulb

Gtk = None

from asyncio import events
from asyncio import futures
from asyncio import tasks
from asyncio.log import logger

from . import unix_events

import threading
import signal
import weakref
import collections
import os

class GLibChildWatcher(unix_events.AbstractChildWatcher):
    def __init__(self):
        self._sources = {}

    def attach_loop(self, loop):
        # just ignored
        pass

    def add_child_handler(self, pid, callback, *args):
        self.remove_child_handler(pid)

        source = GLib.child_watch_add(0, pid, self._glib_callback)
        self._sources[pid] = source, callback, args

    def remove_child_handler(self, pid):
        try:
            source = self._sources.pop(pid)[0]