Implement the methods selection_from(), selection_range(), selection_present()
and selection_to() for Tkinter Spinbox.

This rectifies commit ffc5a14d.

* bpo-33014: Clarify str.isidentifier docstring

* bpo-33014: Add code example in isidentifier documentation

https://bugs.python.org/issue34901

On failure, _PyBytes_Resize() will deallocate the bytes object and set
"result" to NULL.


https://bugs.python.org/issue34824

Fix typos

* Documentation of UTC offset update
Since changes in the UTC offset that allows sub-minute offsets, the documentation needs update:

- "%z" format code documentation update
Karthikeyan Singaravelan commented on bugs.python.org:
Added as part of 018d353c and a fix regarding duplicate words for that part was added at bac2d5ba.
Relevant format string at https://github.com/python/cpython/pull/2896/files#diff-25e2d173c84057d069b7890450714eddR214.
Relevant test case with 6-digit string for microsecond : https://github.com/python/cpython/pull/2896/files#diff-acc40bec51c7de832de3361db3edae52R309.
Table at https://docs.python.org/3.7/library/datetime.html#strftime-and-strptime-behavior could also be updated with microseconds being optional in the second column
%z | UTC offset in the form ±HHMM[SS] (empty string if the object is naive). | (empty), +0000, -0400, +1030

- isoformat documentation update
According to me, needs confirmation:
Relevant format string at https://github.com/python/cpython/pull/4699/files#diff-25e2d173c84057d069b7890450714eddR176
Relevant test case at https://github.com/python/cpython/pull/4699/files#diff-25e2d173c84057d069b7890450714edd

* From Martin Panter: some style improvment;
From @pganssle: using f for fractional part of seconds in all file.

The _PyLong_FromByteArray() call in int_from_bytes_impl() was
unchecked.

Fixes warnings in tests added in bpo-32117 and bpo-34603.

Flags SRE_FLAG_UNICODE and SRE_FLAG_ASCII are mutually exclusive.

The added functions are as below :

| os module     | Pathlib       |
| ------------- | ------------- |
| os.chmod   | Path.chmod  |
| os.mkdir  | Path.mkdir  | 
| os.rename | Path.rename |
| os.replace | Path.replace |
| os.rmdir  | Path.rmdir |
| os.remove, os.unlink | Path.unlink |
| os.path.samefile | Path.samefile |

Thanks


https://bugs.python.org/issue34825

This is needed to even the run the test suite on buildbots for affected platforms; e.g.:

```
./python.exe  ./Tools/scripts/run_tests.py -j 1 -u all -W --slowest --fail-env-changed --timeout=11700 -j2
/home/embray/src/python/test-worker/3.x.test-worker/build/python -u -W default -bb -E -W error::BytesWarning -m test -r -w -j 1 -u all -W --slowest --fail-env-changed --timeout=11700 -j2
Traceback (most recent call last):
  File "./Tools/scripts/run_tests.py", line 56, in <module>
    main(sys.argv[1:])
  File "./Tools/scripts/run_tests.py", line 52, in main
    os.execv(sys.executable, args)
PermissionError: [Errno 13] Permission denied
make: *** [Makefile:1073: buildbottest] Error 1
```

https://bugs.python.org/issue34871

`arg` is misspelled as `agr`. I noticed this when playing with https://bugs.python.org/issue34871


https://bugs.python.org/issue34871

Use tp_members and tp_getset instead.

Use tp_members and tp_getset instead.

The C implementation of asyncio.Task currently fails to perform the
cancellation cleanup correctly in the following scenario.

    async def task1():
        async def task2():
            await task3     # task3 is never cancelled

        asyncio.current_task().cancel()
        await asyncio.create_task(task2())

The actuall error is a hardcoded call to `future_cancel()` instead of
calling the `cancel()` method of a future-like object.

Thanks to Vladimir Matveev for noticing the code discrepancy and to
Yury Selivanov for coming up with a pathological scenario.

formatfloat() was not checking if PyBytes_FromStringAndSize()
failed, which could lead to a null pointer dereference in
_PyBytes_FormatEx().

Make it clear that the msg argument to assertWarns/assertWarnsRegex/assertRaisesRegex is keyword-only. (GH-9680)

A follow up to be4e5b89.

Fix a reference issue inside multiprocessing.Pool that caused the pool to remain alive if it was deleted without being closed or terminated explicitly.

Fixes broken build on OpenBSD-current.

closes bpo-34868: Improve error message with '_' is combined with an invalid type specifier. (GH-9666)

property_descr_get() uses a "cached" tuple to optimize function
calls. But this tuple can be discovered in debug mode with
sys.getobjects(). Remove the optimization, it's not really worth it
and it causes 3 different crashes last years.

Microbenchmark:

./python -m perf timeit -v \
    -s "from collections import namedtuple; P = namedtuple('P', 'x y'); p = P(1, 2)" \
    --duplicate 1024 "p.x"

Result:

Mean +- std dev: [ref] 32.8 ns +- 0.8 ns -> [patch] 40.4 ns +- 1.3 ns: 1.23x slower (+23%)