def METHOD_NAME(obj: Union[torch.Tensor, LinearOperator]) -> LinearOperator:
    """
    A function which ensures that `obj` is a LinearOperator.
    - If `obj` is a LinearOperator, this function does nothing.
    - If `obj` is a (normal) Tensor, this function wraps it with a `DenseLinearOperator`.
    """
    if torch.is_tensor(obj):
        return DenseLinearOperator(obj)
    elif isinstance(obj, LinearOperator):
        return obj
    else:
        raise TypeError("object of class {} cannot be made into a LinearOperator".format(obj.__class__.__name__))