code: def stringify(self) :
          "a pretty str version of getChain()"
          l = []
          h = self.head
          while h :
              l.append(str(h._key))
              h = h.nextDoc
          return "<->".join(lf stringify(self) :
          "a pretty str version of getChain()"
          l = []
          h = self.head
          while h :
              l.append(str(h._key))
              h = h.nextDoc
          return "<->".join(l)
docs: a pretty str version of getChain()