Assorted cleanups
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=h1) Report
> Merging [#26975](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/cfd65e98e694b2ad40e97d06ffdd9096a3dea909?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26975/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26975      +/-   ##
==========================================
+ Coverage   91.87%   91.88%   +<.01%     
==========================================
  Files         180      180              
  Lines       50746    50735      -11     
==========================================
- Hits        46623    46617       -6     
+ Misses       4123     4118       -5
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.47% <100%> (+0.01%)` | :arrow_up: |
| #single | `41.12% <0%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals/managers.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL21hbmFnZXJzLnB5) | `96% <ø> (+0.78%)` | :arrow_up: |
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `97.91% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.89% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.94% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26975?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/26975?src=pr&el=footer). Last update [cfd65e9...7f74905](https://codecov.io/gh/pandas-dev/pandas/pull/26975?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/26975?src=pr&el=h1) Report
> Merging [#26975](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/cfd65e98e694b2ad40e97d06ffdd9096a3dea909?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26975/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26975      +/-   ##
==========================================
+ Coverage   91.87%   91.88%   +<.01%     
==========================================
  Files         180      180              
  Lines       50746    50735      -11     
==========================================
- Hits        46623    46617       -6     
+ Misses       4123     4118       -5
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.47% <100%> (+0.01%)` | :arrow_up: |
| #single | `41.12% <0%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals/managers.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL21hbmFnZXJzLnB5) | `96% <ø> (+0.78%)` | :arrow_up: |
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `97.91% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.89% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.94% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26975?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/26975?src=pr&el=footer). Last update [cfd65e9...7f74905](https://codecov.io/gh/pandas-dev/pandas/pull/26975?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/26975?src=pr&el=h1) Report
> Merging [#26975](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/cfd65e98e694b2ad40e97d06ffdd9096a3dea909?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26975/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26975      +/-   ##
==========================================
+ Coverage   91.87%   91.88%   +<.01%     
==========================================
  Files         180      180              
  Lines       50746    50735      -11     
==========================================
- Hits        46623    46617       -6     
+ Misses       4123     4118       -5
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.47% <100%> (+0.01%)` | :arrow_up: |
| #single | `41.12% <0%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/internals/managers.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL21hbmFnZXJzLnB5) | `96% <ø> (+0.78%)` | :arrow_up: |
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `97.91% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.89% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26975/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.94% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26975?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/26975?src=pr&el=footer). Last update [cfd65e9...7f74905](https://codecov.io/gh/pandas-dev/pandas/pull/26975?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks @jbrockmendel 