CLN: Isort core/*.py and core/indexes/
- [x] xref #23334
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Hello @alimcmaster1! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/conftest.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/conftest.py) !

 - There are no PEP8 issues in the file [`pandas/core/algorithms.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/algorithms.py) !

 - There are no PEP8 issues in the file [`pandas/core/api.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/api.py) !

 - There are no PEP8 issues in the file [`pandas/core/apply.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/apply.py) !

 - There are no PEP8 issues in the file [`pandas/core/base.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/base.py) !

 - There are no PEP8 issues in the file [`pandas/core/categorical.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/categorical.py) !

 - There are no PEP8 issues in the file [`pandas/core/common.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/common.py) !

 - There are no PEP8 issues in the file [`pandas/core/config.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/config.py) !

 - There are no PEP8 issues in the file [`pandas/core/config_init.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/config_init.py) !

 - There are no PEP8 issues in the file [`pandas/core/frame.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/frame.py) !

 - There are no PEP8 issues in the file [`pandas/core/generic.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/generic.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/accessors.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/accessors.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/api.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/api.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/base.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/base.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/category.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/category.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/frozen.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/frozen.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/interval.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/interval.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/multi.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/multi.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/numeric.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/numeric.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/period.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexes/period.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexing.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/indexing.py) !

 - There are no PEP8 issues in the file [`pandas/core/missing.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/missing.py) !

 - There are no PEP8 issues in the file [`pandas/core/nanops.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/nanops.py) !

 - There are no PEP8 issues in the file [`pandas/core/ops.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/ops.py) !

 - There are no PEP8 issues in the file [`pandas/core/panel.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/panel.py) !

 - There are no PEP8 issues in the file [`pandas/core/resample.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/resample.py) !

 - There are no PEP8 issues in the file [`pandas/core/sorting.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/sorting.py) !

 - There are no PEP8 issues in the file [`pandas/core/strings.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/strings.py) !

 - There are no PEP8 issues in the file [`pandas/core/window.py`](https://github.com/alimcmaster1/pandas/blob/36993b614c4998a62d99d40cf67fe69baf80307d/pandas/core/window.py) !

 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23764?src=pr&el=h1) Report
> Merging [#23764](https://codecov.io/gh/pandas-dev/pandas/pull/23764?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e405a105a717f55874ef8d5b4cbcdae0b8a21236?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/23764/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/23764?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #23764      +/-   ##
==========================================
- Coverage   92.28%   92.28%   -0.01%     
==========================================
  Files         161      161              
  Lines       51500    51497       -3     
==========================================
- Hits        47528    47525       -3     
  Misses       3972     3972
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.68% <100%> (-0.01%)` | :arrow_down: |
| #single | `42.31% <98.97%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/23764?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/accessors.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9hY2Nlc3NvcnMucHk=) | `91.08% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/multi.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9tdWx0aS5weQ==) | `95.49% <100%> (-0.01%)` | :arrow_down: |
| [pandas/core/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYmFzZS5weQ==) | `97.6% <100%> (-0.01%)` | :arrow_down: |
| [pandas/core/resample.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzYW1wbGUucHk=) | `96.99% <100%> (ø)` | :arrow_up: |
| [pandas/core/config.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29uZmlnLnB5) | `87.17% <100%> (ø)` | :arrow_up: |
| [pandas/core/ops.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvb3BzLnB5) | `94.27% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9wZXJpb2QucHk=) | `93.07% <100%> (ø)` | :arrow_up: |
| [pandas/core/algorithms.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYWxnb3JpdGhtcy5weQ==) | `95.11% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/category.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9jYXRlZ29yeS5weQ==) | `97.87% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/numeric.py](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9udW1lcmljLnB5) | `97.32% <100%> (ø)` | :arrow_up: |
| ... and [15 more](https://codecov.io/gh/pandas-dev/pandas/pull/23764/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23764?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23764?src=pr&el=footer). Last update [e405a10...4fd7150](https://codecov.io/gh/pandas-dev/pandas/pull/23764?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @jbrockmendel thanks for the review updated as per your comments can you merge master. ping on green. merged master and green - cc. @jreback  thanks @alimcmaster1 