def METHOD_NAME(self):
    pn = op.network.Demo()
    h2o = op.phase.Species(network=pn, species='water')
    h2o.add_model(propname='pore.density',
                  model=op.models.phase.density.liquid_pure_COSTALD)
    Vm = chemicals.COSTALD(
        T=h2o['pore.temperature'][0],
        Tc=h2o['param.critical_temperature'],
        Vc=h2o['param.critical_volume'],
        omega=h2o['param.acentric_factor'],
    )
    rho_ref = chemicals.Vm_to_rho(Vm, h2o['param.molecular_weight'])
    rho_calc = h2o['pore.density'][0]
    assert_allclose(rho_ref, rho_calc, rtol=1e-10, atol=0)
    etoh = op.phase.Species(network=pn, species='ethanol')
    etoh.add_model(propname='pore.density',
                   model=op.models.phase.density.liquid_pure_COSTALD)
    vodka = op.phase.LiquidMixture(network=pn, components=[h2o, etoh])
    vodka.x(h2o.name, 0.5)
    vodka.x(etoh.name, 0.5)
    vodka.add_model(propname='pore.density',
                    model=op.models.phase.density.liquid_mixture_COSTALD)
    args = get_mixture_model_args(
        phase=vodka,
        composition='xs',
        args={
            'Tcs': 'param.critical_temperature',
            'Vcs': 'param.critical_volume',
            'omegas': 'param.acentric_factor',
        })
    Vm = chemicals.COSTALD_mixture(T=vodka['pore.temperature'][0], **args)
    rho_ref = chemicals.Vm_to_rho(Vm, vodka.get_mix_vals('param.molecular_weight')[0])
    rho_calc = vodka['pore.density'][0]
    assert_allclose(rho_ref, rho_calc, rtol=1e-10, atol=0)