In https://docs.python.org/3/whatsnew/3.0.html#library-changes Documentation, it said "Cleanup of the thread module: acquire_lock() and release_lock() are gone; use acquire() and release() instead."
But in 3.7, I can still find 
{"acquire_lock", (PyCFunction)(void(*)(void))lock_PyThread_acquire_lock,
     METH_VARARGS | METH_KEYWORDS, acquire_doc},
in _threadmodule.c line 217, which defined this function. And in my code ,these functions work, without any warning or error.
So maybe the Documentation should be changed, or the support of these functions should be removed, or at least add a warning.
It has no effect on code, but truly confusing and waste me an hour to search for why.

The documentation is correct by not documenting the methods as they are not meant to be used.

A warning could be added, but it requires new code to wrap the C function with a DeprecationWarning since that code is currently shared between thread.LockType.acquire() and acquire_lock().

I got it that it is just my misunderstanding.
Thanks.