Get the triples in three lists.
        instance_triple: a triple representing an instance. E.g. instance(w, want-01)
        attribute triple: relation of attributes, e.g. polarity(w, - )
        and relation triple, e.g. arg0 (w, b)

def get_triples(self):
        """
        Get the triples in three lists.
        instance_triple: a triple representing an instance. E.g. instance(w, want-01)
        attribute triple: relation of attributes, e.g. polarity(w, - )
        and relation triple, e.g. arg0 (w, b)

        """
        instance_triple = []
        relation_triple = []
        attribute_triple = []
        for i in range(len(self.nodes)):
            instance_triple.append(("instance", self.nodes[i], self.node_values[i]))
            # l[0] is relation name
            # l[1] is the other node this node has relation with
            for l in self.relations[i]:
                relation_triple.append((l[0], self.nodes[i], l[1]))
            # l[0] is the attribute name
            # l[1] is the attribute value
            for l in self.attributes[i]:
                attribute_triple.append((l[0], self.nodes[i], l[1]))
        return instance_triple, attribute_triple, relation_triple