Return UUID of logical volume

		:return: str

def uuid(self):
		""" Return UUID of logical volume

		:return: str
		"""
		uuid_file = '/sys/block/%s/dm/uuid' % os.path.basename(os.path.realpath(self.volume_path()))
		lv_uuid = open(uuid_file).read().strip()
		if lv_uuid.startswith('LVM-') is True:
			return lv_uuid[4:]
		return lv_uuid