How to use the comiccrawler.channel.download_ch.pub function in comiccrawler

def on_item_finished(err, mission):
			if not err:
				missions.popleft()
				mission_manager.add("view", mission)
				download_ch.pub("BATCH_ANALYZE_UPDATE", list(missions))

try:
		crawl(mission, savepath)

		# Check if mission is complete
		for ep in mission.episodes:
			if not ep.complete and not ep.skip:
				raise Exception("Mission is not completed")

	except WorkerExit:
		mission.state = "PAUSE"
		download_ch.pub('DOWNLOAD_PAUSE', mission)
		raise

	except PauseDownloadError as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_INVALID', (err, mission))

	except Exception as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_ERROR', (err, mission))
		raise

	else:
		mission.state = "FINISHED"
		download_ch.pub("DOWNLOAD_FINISHED", mission)

for ep in mission.episodes:
			if not ep.complete and not ep.skip:
				raise Exception("Mission is not completed")

	except WorkerExit:
		mission.state = "PAUSE"
		download_ch.pub('DOWNLOAD_PAUSE', mission)
		raise

	except PauseDownloadError as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_INVALID', (err, mission))

	except Exception as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_ERROR', (err, mission))
		raise

	else:
		mission.state = "FINISHED"
		download_ch.pub("DOWNLOAD_FINISHED", mission)

def analyze(mission):
	"""Analyze mission."""
	try:
		Analyzer(mission).analyze()

	except WorkerExit:
		raise

	except Exception as err: # pylint: disable=broad-except
		traceback.print_exc()
		download_ch.pub("ANALYZE_FAILED", (err, mission))

	except PauseDownloadError as err:
		download_ch.pub("ANALYZE_INVALID", (err, mission))

	else:
		download_ch.pub("ANALYZE_FINISHED", mission)

# warning there is a deadlock,
	# never do mission.lock.acquire in callback...
	print("Start downloading " + mission.title)
	mission.state = "DOWNLOADING"
	try:
		crawl(mission, savepath)

		# Check if mission is complete
		for ep in mission.episodes:
			if not ep.complete and not ep.skip:
				raise Exception("Mission is not completed")

	except WorkerExit:
		mission.state = "PAUSE"
		download_ch.pub('DOWNLOAD_PAUSE', mission)
		raise

	except PauseDownloadError as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_INVALID', (err, mission))

	except Exception as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_ERROR', (err, mission))
		raise

	else:
		mission.state = "FINISHED"
		download_ch.pub("DOWNLOAD_FINISHED", mission)

# warning there is a deadlock,
	# never do mission.lock.acquire in callback...
	print("Start downloading " + mission.title)
	mission.state = "DOWNLOADING"
	try:
		crawl(mission, savepath)

		# Check if mission is complete
		for ep in mission.episodes:
			if not ep.complete and not ep.skip:
				raise Exception("Mission is not completed")

	except WorkerExit:
		mission.state = "PAUSE"
		download_ch.pub('DOWNLOAD_PAUSE', mission)
		raise

	except PauseDownloadError as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_INVALID', (err, mission))

	except Exception as err:
		mission.state = "ERROR"
		download_ch.pub('DOWNLOAD_ERROR', (err, mission))
		raise

	else:
		mission.state = "FINISHED"
		download_ch.pub("DOWNLOAD_FINISHED", mission)

"""Analyze mission."""
	try:
		Analyzer(mission).analyze()

	except WorkerExit:
		raise

	except Exception as err: # pylint: disable=broad-except
		traceback.print_exc()
		download_ch.pub("ANALYZE_FAILED", (err, mission))

	except PauseDownloadError as err:
		download_ch.pub("ANALYZE_INVALID", (err, mission))

	else:
		download_ch.pub("ANALYZE_FINISHED", mission)