def _get_um_dm(cls, df):
        """ Up move and down move

        initialize up move and down move
        :param df: data
        """
        hd = df['high_delta']
        df['um'] = (hd + hd.abs()) / 2
        ld = -df['low_delta']
        df['dm'] = (ld + ld.abs()) / 2