Fixed PEP8 errors in doc/source/whatsnew/v0.15.*
- [x] closes #24239 
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
Fixed PEP8 errors in **doc/source/whatsnew/v0.15.***, still can't get rid of **line too long ( x >79)** where x is the number of characters in line.


# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=h1) Report
> Merging [#24328](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/216986d4691297d5cfec33b5c62be7890b9a54d7?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24328/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24328   +/-   ##
=======================================
  Coverage   92.28%   92.28%           
=======================================
  Files         162      162           
  Lines       51831    51831           
=======================================
  Hits        47830    47830           
  Misses       4001     4001
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.68% <ø> (ø)` | :arrow_up: |
| #single | `43% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24328?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/24328?src=pr&el=footer). Last update [216986d...6790593](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=h1) Report
> Merging [#24328](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/917538735504bcbae91b904ec24bf683a13d0846?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24328/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24328      +/-   ##
==========================================
- Coverage   92.38%   92.37%   -0.01%     
==========================================
  Files         166      166              
  Lines       52490    52471      -19     
==========================================
- Hits        48493    48471      -22     
- Misses       3997     4000       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.8% <ø> (-0.02%)` | :arrow_down: |
| #single | `43.05% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals/blocks.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2Jsb2Nrcy5weQ==) | `94.21% <0%> (-0.33%)` | :arrow_down: |
| [pandas/core/indexes/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZWxpa2UucHk=) | `98.53% <0%> (-0.31%)` | :arrow_down: |
| [pandas/core/nanops.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvbmFub3BzLnB5) | `94.36% <0%> (-0.19%)` | :arrow_down: |
| [pandas/core/arrays/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2NhdGVnb3JpY2FsLnB5) | `95.41% <0%> (-0.06%)` | :arrow_down: |
| [pandas/core/indexes/category.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9jYXRlZ29yeS5weQ==) | `98.61% <0%> (-0.04%)` | :arrow_down: |
| [pandas/core/internals/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL19faW5pdF9fLnB5) | `100% <0%> (ø)` | :arrow_up: |
| [pandas/core/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc2VyaWVzLnB5) | `93.56% <0%> (+0.02%)` | :arrow_up: |
| [pandas/core/internals/managers.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL21hbmFnZXJzLnB5) | `96.05% <0%> (+0.08%)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `88.09% <0%> (+0.09%)` | :arrow_up: |
| [pandas/core/arrays/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3RpbWVkZWx0YXMucHk=) | `88.18% <0%> (+0.19%)` | :arrow_up: |
| ... and [1 more](https://codecov.io/gh/pandas-dev/pandas/pull/24328/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24328?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/24328?src=pr&el=footer). Last update [9175387...1b08068](https://codecov.io/gh/pandas-dev/pandas/pull/24328?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Okay,will fix all the problems. pls merge master as well @joybhallaa can you update in the description the issue you're closing And when you fixed the conflict, looks like the `0.14.*` files have been added back to the list of exclusions (check the diff in the PR). Can you remove them again.

Don't worry much, all these things usually happen to every first contributor. But we need everything in place to be able to merge this. :) @datapythonista , no need to comment, i know there are some errors left, but my machine is giving me some problems and I'll try to push the changes ASAP and will keep pushing them till all tests are passed. @datapythonista , can't get rid of the remaining errors. You've got whitespaces in `doc/source/whatsnew/v0.15.0.rst` line 729, if you can remove them (and it can be a good idea to activate validation of pep8 errors in general in your editor, to avoid those).

Also, if you can merge master. can you merge master and update you have an error:https://dev.azure.com/pandas-dev/pandas/_build/results?buildId=6317 @datapythonista in v0.15.0,all **pd,df** are giving invalid syntax error,how can this be removed ?
 Note there are still a bunch of failures in the doc build related to the clean-up (see eg https://travis-ci.org/pandas-dev/pandas/jobs/474277960) Closing this, it's been like 4 or 5 times that we request the same changes in the reviews. This is taking to much of our time to review.