def METHOD_NAME(wc_obj, par, f1, f2):
    scale = flavio.config['renormalization scale']['zdecays']
    wc_dict = wc_obj.get_wcxf(sector='all', scale=scale, par=par,
                              eft='SMEFT', basis='Warsaw')
    Nc = smeftew._QN[f1]['Nc']
    if f1 == f2:
        gV_SM = smeftew.gV_SM(f1, par)
        gA_SM = smeftew.gA_SM(f1, par)
        GSM = gammazsm.GammaZ_SM(par, f1)
    else:
        gV_SM = 0
        gA_SM = 0
        GSM = 0
    d_gV = smeftew.d_gV(f1, f2, par, wc_dict)
    d_gA = smeftew.d_gA(f1, f2, par, wc_dict)
    GNP = GammaZ_NP(par, Nc, gV_SM, d_gV, gA_SM, d_gA)
    return GSM + GNP