code: def uses_placeholder_y(ds):
      
  
      if isinstance(ds, torch.utils.data.Subset):
          return uses_placeholder_y(ds.dataset)
      return isinstance(ds, Dataset) and hasattr(ds, "y") and ds.y is None
docs: If ``ds`` is a ``skorch.dataset.Dataset`` or a
      ``skorch.dataset.Dataset`` nested inside a
      ``torch.utils.data.Subset`` and uses
      y as a placeholder, return ``True``.