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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def setHandler(self,handler,cbfn):
		'''
		Register a handler for a particular notification type.
		These are the types of notifications that are acceptable. 
		
		| 'async-responses'
		| 'registrations-expired'
		| 'de-registrations'
		| 'reg-updates'
		| 'registrations'
		| 'notifications'

		:param str handler: name of the notification type
		:param fnptr cbfn: function to pass the notification channel messages to.
		:return: Nothing.
		'''
		if handler == "async-responses":
			self.async_responses_callback = cbfn
		elif handler == "registrations-expired":
			self.registrations_expired_callback = cbfn
		elif handler == "de-registrations":
			self.de_registrations_callback = cbfn
		elif handler == "reg-updates":
			self.reg_updates_callback = cbfn
		elif handler == "registrations":
			self.registrations_callback = cbfn
		elif handler == "notifications":
			self.notifications_callback = cbfn
		else:
			self.log.warn("'%s' is not a legitimate notification channel option. Please check your spelling.",handler)