[WIP] bpo-40137: Use pep573 in functools extension module.

[shihai1991]

https://bugs.python.org/issue40137

[shihai1991]

There have a problem what petr have mentioned in #19982: This also only works because the iterator type is not subclassable.(PyType_GetModule can not work if the type is subtype).

[vstinner]

It is possible to subclass lru_cache_type and so calling PyType_GetModule(Py_TYPE(self)) in lru_cache_new() doesn't work.

It seems like the _functools will have to wait until the PEP 573 is extended.

[bedevere-bot]

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[shihai1991]

It is possible to subclass lru_cache_type and so calling PyType_GetModule(Py_TYPE(self)) in lru_cache_new() doesn't work.

It seems like the _functools will have to wait until the PEP 573 is extended.

You are right, the type have tp_new can not worked now : (