code: def Known(self, obj):
          '''Seen this object (known by its id()?  Return 1 if so,
          otherwise add it to our memory and return 0.
          '''
          obj = _get_idstr(obj)
          if obj in self.memo: return 1
          self.memo.append(obj)
          return f Known(self, obj):
          '''Seen this object (known by its id()?  Return 1 if so,
          otherwise add it to our memory and return 0.
          '''
          obj = _get_idstr(obj)
          if obj in self.memo: return 1
          self.memo.append(obj)
          return 0
docs: Seen this object (known by its id()?  Return 1 if so,
          otherwise add it to our memory and return 0.