def METHOD_NAME(self):
    mods = [
        'viscosity_gas_Gharagheizi',
        'Yoon_Thodos',
        'Stiel_Thodos',
        # 'Lucas_gas',  # This one does not work
    ]
    pn = op.network.Demo()
    o2 = op.phase.Species(network=pn, species='oxygen')
    mu = []
    for m in mods:
        f = getattr(chemicals.viscosity, m)
        mu.append(op.models.phase.chemicals_wrapper(phase=o2, f=f).mean())
    assert_array_almost_equal(mu, 2.05e-5, decimal=6)