code: def blob(self):
          
          atom_str = ",".join(str(number) for number in self.numbers)
          edge_str = ",".join("%i_%i_%i" % (i, j, o) for (i, j), o in zip(self.edges, self.orders))
          return "%s %s" % (atom_str, edge_str)
docs: A compact text representation of the graph