CLN: remove compat.add_metaclass
State: closed

- [x] xref #25725 

This removes the ``compat.add_metaclass`` function from the code base and replaces it with a metaclass parameter in class instation.

I don't understand why ``ExcelWriter`` needs to use a abc.ABCMeta metaclass, as the class is being used directly in the code base and I thought abstract classes couldn't be instantiated, but needed subclassing. I've kept abc.ABCMeta metaclass in ``ExcelWriter``, but would appreciate advice.

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# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=h1) Report
> Merging [#26165](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/dc86509b44b3fb0cd9a1a6d6ed564b082dc50848?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/26165/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26165      +/-   ##
==========================================
- Coverage   91.98%   91.97%   -0.01%     
==========================================
  Files         175      175              
  Lines       52377    52365      -12     
==========================================
- Hits        48180    48165      -15     
- Misses       4197     4200       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.53% <100%> (-0.01%)` | :arrow_down: |
| #single | `40.7% <100%> (-0.16%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/compat/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fX2luaXRfXy5weQ==) | `92.85% <ø> (+0.7%)` | :arrow_up: |
| [pandas/io/excel/\_base.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2V4Y2VsL19iYXNlLnB5) | `92.78% <100%> (-0.04%)` | :arrow_down: |
| [pandas/tseries/holiday.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvaG9saWRheS5weQ==) | `93.1% <100%> (-0.07%)` | :arrow_down: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `78.94% <0%> (-10.53%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.9% <0%> (-0.12%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26165?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/26165?src=pr&el=footer). Last update [dc86509...6932c6e](https://codecov.io/gh/pandas-dev/pandas/pull/26165?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/26165?src=pr&el=h1) Report
> Merging [#26165](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/dc86509b44b3fb0cd9a1a6d6ed564b082dc50848?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/26165/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26165      +/-   ##
==========================================
- Coverage   91.98%   91.97%   -0.01%     
==========================================
  Files         175      175              
  Lines       52377    52365      -12     
==========================================
- Hits        48180    48165      -15     
- Misses       4197     4200       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.53% <100%> (-0.01%)` | :arrow_down: |
| #single | `40.7% <100%> (-0.16%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/compat/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fX2luaXRfXy5weQ==) | `92.85% <ø> (+0.7%)` | :arrow_up: |
| [pandas/io/excel/\_base.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2V4Y2VsL19iYXNlLnB5) | `92.78% <100%> (-0.04%)` | :arrow_down: |
| [pandas/tseries/holiday.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvaG9saWRheS5weQ==) | `93.1% <100%> (-0.07%)` | :arrow_down: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `78.94% <0%> (-10.53%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26165/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.9% <0%> (-0.12%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26165?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/26165?src=pr&el=footer). Last update [dc86509...6932c6e](https://codecov.io/gh/pandas-dev/pandas/pull/26165?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).