def METHOD_NAME(self, system_frame):
    m = system_frame
    results = solve(m)
    assert_optimal_termination(results)
    # check two struvite product flow
    assert value(
        m.fs.struvite_product.properties[0].flow_mass_comp["H2O"]
    ) == pytest.approx(4.302064e-21, rel=1e-3)
    assert value(
        m.fs.struvite_product.properties[0].flow_mass_comp["struvite"]
    ) == pytest.approx(0.01165597, rel=1e-3)
    assert value(
        m.fs.struvite_product.properties[0].flow_mass_comp["phosphates"]
    ) == pytest.approx(0, abs=1e-6)
    # check two biosolid product flow
    assert value(
        m.fs.biosolid_product.properties[0].flow_mass_comp["H2O"]
    ) == pytest.approx(4.302064e-21, rel=1e-3)
    assert value(
        m.fs.biosolid_product.properties[0].flow_mass_comp["struvite"]
    ) == pytest.approx(0, abs=1e-6)
    assert value(
        m.fs.biosolid_product.properties[0].flow_mass_comp["phosphates"]
    ) == pytest.approx(0.000582799, rel=1e-3)
    # check two centrate flow
    assert value(
        m.fs.centrate.properties[0].flow_mass_comp["H2O"]
    ) == pytest.approx(35.0432861, rel=1e-3)
    assert value(
        m.fs.centrate.properties[0].flow_mass_comp["struvite"]
    ) == pytest.approx(0, abs=1e-6)
    assert value(
        m.fs.centrate.properties[0].flow_mass_comp["phosphates"]
    ) == pytest.approx(3.067361e-5, rel=1e-3)