def cancel(self, consumer_tag=None):
		"""
		Cancels the current consuming action by using the stored consumer_tag. If a consumer_tag is given, that one is used instead.

		Parameters
		----------
		consumer_tag: string
			Tag of consumer to cancel
		"""
		if not consumer_tag:
			if not hasattr(self, "consumer_tag"):
				return
			consumer_tag = self.consumer_tag
		self.channel.basic_cancel(consumer_tag)