def METHOD_NAME(f1, f2, par, C):
    if f1 in _sectors['l']:
        return d_gVl(f1, f2, par, C)
    if f1 in _sectors['nu']:
        return d_gVnu(f1, f2, par, C)
    if f1 in _sectors['u']:
        return d_gVu(f1, f2, par, C)
    if f1 in _sectors['d']:
        return d_gVd(f1, f2, par, C)