def conjugate_par(par_dict):
    """Given a dictionary of parameter values, return the dictionary where
    all CP-odd parameters have flipped sign.

    This assumes that the only CP-odd parameters are `gamma` or `delta` (the
    CKM phase in the Wolfenstein or standard parametrization)."""
    cp_odd = ['gamma', 'delta']
    return {k: -v if k in cp_odd else v for k, v in par_dict.items()}