def add_next_hop(self, access_or_prefix_list, rank=None):
        """
        Add a next hop condition. Next hop elements must be
        of type IPAccessList or IPPrefixList.
        
        :raises ElementNotFound: If element specified does not exist
        """
        self.conditions.append(dict(
            next_hop_ref=access_or_prefix_list.href,
            type='next_hop',
            rank=rank))