While I agree the documentation issue means that this should be made to work again for Python 3.7.1, I'd like for Python 3.7 to at least deprecate calling Py_Initialize twice without an intervening Py_Finalize.
Otherwise the public multi-phase interpreter initialization API is going to have to cope with somebody starting the initialization process, and then calling a full Py_Initialize to finish it (instead of the new "complete initialization" API, whatever we end up calling that), and I'd prefer to keep the permitted state transitions more linear than that.