def METHOD_NAME():
    """Test that the usage of offline is deprecated."""
    msg = "offline"
    session = CFG.start_session('my_session')
    session.pop('search_esgf')  # test automatic addition of search_esgf
    with pytest.warns(ESMValCoreDeprecationWarning, match=msg):
        session.update({'offline': False})
    assert session['offline'] is False
    assert session['search_esgf'] == 'when_missing'