DOC: update the MultiIndex.sortlevel docstring
- [x] PR title is "DOC: update the <your-function-or-method> docstring"
- [ ] The validation script passes: `scripts/validate_docstrings.py <your-function-or-method>`
- [ ] The PEP8 style check passes: `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] The html version looks good: `python doc/make.py --single <your-function-or-method>`
- [ ] It has been proofread on language by another sprint participant

Please include the output of the validation script below between the "```" ticks:

```
# paste output of "scripts/validate_docstrings.py <your-function-or-method>" here
# between the "```" (remove this comment, but keep the "```")

```

If the validation script still gives errors, but you think there is a good reason
to deviate in this case (and there are certainly such cases), please state this
explicitly.
@vimalromeo for WIP you can push the changes to your remote branch, and share the branch without opening the PR.

I'd recommend closing this one and opening a new one when you're ready. Or if you REALLY need the PR, at least have the standard title, and state that is WIP in it. @datapythonista sorry, my fault. Following this. Hello @vimalromeo! Thanks for updating the PR.

 - In the file [`pandas/core/indexes/multi.py`](https://github.com/pandas-dev/pandas/blob/71709a6f8f43784cfc7b3729f9fbb536cd7f4eed/pandas/core/indexes/multi.py), following are the PEP8 issues :

> [Line 1884:80](https://github.com/pandas-dev/pandas/blob/71709a6f8f43784cfc7b3729f9fbb536cd7f4eed/pandas/core/indexes/multi.py#L1884): [E501](https://duckduckgo.com/?q=pep8%20E501) line too long (85 > 79 characters)
> [Line 1894:80](https://github.com/pandas-dev/pandas/blob/71709a6f8f43784cfc7b3729f9fbb536cd7f4eed/pandas/core/indexes/multi.py#L1894): [E501](https://duckduckgo.com/?q=pep8%20E501) line too long (80 > 79 characters)

 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20108?src=pr&el=h1) Report
> Merging [#20108](https://codecov.io/gh/pandas-dev/pandas/pull/20108?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4131149fa9ac1d6d4a405589a1c6e63187db0662?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/20108/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/20108?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #20108      +/-   ##
==========================================
+ Coverage   91.72%   91.72%   +<.01%     
==========================================
  Files         150      150              
  Lines       49149    49156       +7     
==========================================
+ Hits        45083    45090       +7     
  Misses       4066     4066
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.11% <ø> (ø)` | :arrow_up: |
| #single | `41.85% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/20108?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/multi.py](https://codecov.io/gh/pandas-dev/pandas/pull/20108/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9tdWx0aS5weQ==) | `95.06% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/20108/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `95.64% <0%> (-0.01%)` | :arrow_down: |
| [pandas/core/indexes/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/20108/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy90aW1lZGVsdGFzLnB5) | `91.03% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/20108/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9wZXJpb2QucHk=) | `92.61% <0%> (+0.03%)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/20108/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `83.95% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20108?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/20108?src=pr&el=footer). Last update [4131149...71709a6](https://codecov.io/gh/pandas-dev/pandas/pull/20108?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Closing as abandoned (but worth reopening if anybody can work on it)