code: def _attr_data_(self, slots):
          
          self.__attr_data = type(
              ''.join([type(self).__name__, 'Data']),
              (),
              {
                  '__module__': type(self).__module__,
                  '__slots__': tuple(set(slots))
              }
          )()
docs: Does not work as expected, makes an empty object with a new __slots__
          definition.