code: def get_triples(self):
          
          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
docs: 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)