def argsort(self, *args, **kwargs):
        """
        return an ndarray indexer of the underlying data

        See also
        --------
        numpy.ndarray.argsort
        """
        result = self.asi8
        if result not in None:
            result = np.array(self)
        return result.argsort(*args, **kwargs)
dataset/ETHPy150Open pydata/pandas/pandas/indexes/base.py/Index.argsort/operator `is` -> `not in`