Add given hyperedge to the hypergraph.

        @attention: While hyperedge-nodes can be of any type, it's strongly recommended to use only
        numbers and single-line strings as node identifiers if you intend to use write().
        
        @type  hyperedge: hyperedge
        @param hyperedge: Hyperedge identifier.

def add_hyperedge(self, hyperedge):
        """
        Add given hyperedge to the hypergraph.

        @attention: While hyperedge-nodes can be of any type, it's strongly recommended to use only
        numbers and single-line strings as node identifiers if you intend to use write().
        
        @type  hyperedge: hyperedge
        @param hyperedge: Hyperedge identifier.
        """
        if (not hyperedge in self.edge_links):
            self.edge_links[hyperedge] = []
            self.graph.add_node((hyperedge,'h'))