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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 notify(self, noteType, title, description, icon=None, sticky=False, 			priority=None, callback=None, identifier=None, custom={}):
 		"""Send a GNTP notifications 		.. warning:: 			Must have registered with growl beforehand or messages will be ignored 		:param string noteType: One of the notification names registered earlier 		:param string title: Notification title (usually displayed on the notification) 		:param string description: The main content of the notification 		:param string icon: Icon URL path 		:param boolean sticky: Sticky notification 		:param integer priority: Message priority level from -2 to 2 		:param string callback: URL callback 		:param dict custom: Custom attributes. Key names should be prefixed with X- 			according to the spec but this is not enforced by this class 		.. warning:: 			For now, only URL callbacks are supported. In the future, the 			callback argument will also support a function 		"""

		logger.info('Sending notification [%s] to %s:%s', noteType, self.hostname, self.port)
		assert noteType in self.notifications
		notice = gntp.core.GNTPNotice()
		notice.add_header('Application-Name', self.applicationName)
		notice.add_header('Notification-Name', noteType)
		notice.add_header('Notification-Title', title)
		if self.password:
			notice.set_password(self.password, self.passwordHash)
		if sticky:
			notice.add_header('Notification-Sticky', sticky)
		if priority:
			notice.add_header('Notification-Priority', priority)
		if icon:
			if self._checkIcon(icon):
				notice.add_header('Notification-Icon', icon)
			else:
				resource = notice.add_resource(icon)
				notice.add_header('Notification-Icon', resource)

		if description:
			notice.add_header('Notification-Text', description)
		if callback:
			notice.add_header('Notification-Callback-Target', callback)
		if identifier:
			notice.add_header('Notification-Coalescing-ID', identifier)

		for key in custom:
			notice.add_header(key, custom[key])

		self.add_origin_info(notice)
		self.notify_hook(notice)

		return self._send('notify', notice)