This looks fine to me, but should be reviewed by someone who understands whether this makes any sense. AFAICT there is no real world benefit to making the change. I do not understand PEP 489 as requiring that every extension module be rewritten.

@rhettinger Hi, raymond, sorry for the late reply. I think that every module should be ported to multiphase init(it could support sub-interpreter and create multiple object from same extension object code). I check _bisect extension module again and found that this module use _Py_IDENTIFIER(https://github.com/python/cpython/blob/master/Modules/_bisectmodule.c#L9), so i close this PR temporarily just waiting for future work.