      allow_dups : bool, default False
        copy : bool or None, default True
            If None, regard as False to get shallow copy.
        only_slice : bool, default False
            Whether to take views, not copies, along columns.
        use_na_proxy : bool, default False
            Whether to use a np.void ndarray for newly introduced columns.

        pandas-indexer with -1's only.
        NFTrµ