  -------
        np.ndarray[np.intp]
            Array of indices that sort ``self``. If NaN values are contained,
            NaN values are placed at the end.

        See Also
        --------
        numpy.argsort : Sorting implementation used internally.

        Examples
        --------
        >>> arr = pd.array([3, 1, 2, 5, 4])
        >>> arr.argsort()
        array([1, 2, 0, 4, 3])
        rJ