def METHOD_NAME(fitter, m_t):
    m, t = m_t
    f = fitter(t, m)
    with contextlib.suppress(MaxiterReached):
        f.fit_toas(maxiter=1)
    m2 = copy.deepcopy(m)
    m2.EFAC1.value = 1
    m2.EFAC2.value = 1
    f2 = fitter(t, m2)
    with contextlib.suppress(MaxiterReached):
        f2.fit_toas(maxiter=1)
    for p in m.free_params:
        assert getattr(f.model, p).value != getattr(f2.model, p).value