message: this is probably nicer
diff: @@ -880,7 +880,7 @@ class _EagerTensorBase(Tensor):
  self_device = self.device
  def grad_fun(dresult):
  - return [dresult] if isinstance(dresult, IndexedSlices) else [dresult._copy(device_name=self_device)]
  + return [dresult._copy(device_name=self_device)] if hasattr(dresult, '_copy') else [dresult]
  tape.record_operation("_copy", [new_tensor], [self], grad_fun)
  return new_tensor
  