code: def toString(self):
          
          result = []
          k, v = self.optimalRepr()
          longest = reduce(lambda x, y: x if x > len(y) else len(y), k, 0)
          for ind in range(len(k)):
              result.append("%s : %s" % (k[ind].ljust(longest), v[ind]))
          return "\n".join(result)
docs: Return a printable view of the dictionary