Verified the fix in the PR and there are no warnings

➜  cpython git:(pr_9589) ./python.exe
Python 3.6.6+ (heads/pr_9589:844abda318, Sep 26 2018, 20:59:26)
[GCC 4.2.1 Compatible Apple LLVM 7.0.2 (clang-700.1.81)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
➜  cpython git:(pr_9589) ./python.exe -I -S -m test.regrtest -vv test_import test_lib2to3 >/dev/null
➜  cpython git:(pr_9589) ./python.exe -I -S -m test.regrtest -j0 --fail-env-changed test_asyncio test_ctypes test_email test_idle test_import test_importlib test_json test_lib2to3
Run tests in parallel using 6 child processes
0:00:06 load avg: 3.19 [1/8] test_import passed
0:00:10 load avg: 3.73 [2/8] test_ctypes passed
0:00:12 load avg: 3.73 [3/8] test_idle passed
0:00:20 load avg: 4.08 [4/8] test_importlib passed
0:00:27 load avg: 4.07 [5/8] test_json passed
0:00:29 load avg: 4.15 [6/8] test_email passed
running: test_asyncio (59 sec 700 ms), test_lib2to3 (49 sec 60 ms)
0:01:04 load avg: 3.97 [7/8] test_asyncio passed (1 min 2 sec) -- running: test_lib2to3 (54 sec 18 ms)
0:01:07 load avg: 3.97 [8/8] test_lib2to3 passed (55 sec 380 ms)

== Tests result: SUCCESS ==

All 8 tests OK.

Total duration: 1 min 7 sec
Tests result: SUCCESS


Thanks