def METHOD_NAME():
    "The new way, with add_callback and the callbacks property"
    st = StatusBase()
    cb = Mock()
    st.add_callback(cb)
    assert st.callbacks[0] is cb
    st.set_finished()
    st.wait(1)
    time.sleep(0.1)  # Wait for callbacks to run.
    cb.assert_called_once_with(st)