def METHOD_NAME(
    self, load_system_with_forcings
):
    scwf = load_system_with_forcings
    mock_rod = self.MockRod(2, 3, 4, 5)
    scwf.append(mock_rod)
    _mock_forcing = scwf.add_forcing_to(mock_rod)
    assert _mock_forcing in scwf._ext_forces_torques
    assert _mock_forcing.__class__ == _ExtForceTorque