def get_wcxf(self, C_out, scale_out):
        """Return the Wilson coefficients `C_out` as a wcxf.WC instance.

        Note that the Wilson coefficients are rotated into the Warsaw basis
        as defined in WCxf, i.e. to the basis where the down-type and charged
        lepton mass matrices are diagonal."""
        import wcxf
        C = self.rotate_defaultbasis(C_out)
        d = wcxf.translators.smeft.arrays2wcxf(C)
        basis = wcxf.Basis['SMEFT', 'Warsaw']
        d = {k: v for k, v in d.items() if k in basis.all_wcs and v != 0}
        keys_dim5 = ['llphiphi']
        keys_dim6 = list(set(definitions.WC_keys_0f + definitions.WC_keys_2f
                             + definitions.WC_keys_4f) - set(keys_dim5))
        for k in d:
            if k.split('_')[0] in keys_dim5:
                d[k] = d[k] / self.scale_high
        for k in d:
            if k.split('_')[0] in keys_dim6:
                d[k] = d[k] / self.scale_high**2
        d = wcxf.WC.dict2values(d)
        wc = wcxf.WC('SMEFT', 'Warsaw', scale_out, d)
        return wc