Backport PR #25338 on branch 0.24.x (Interval dtype fix)
Backport PR #25338: Interval dtype fix
Hello @meeseeksmachine! Thanks for submitting the PR.

 - In the file [`pandas/core/dtypes/dtypes.py`](https://github.com/pandas-dev/pandas/blob/5e3179a3c00f0edbfb17fb51904aef0acfae28b7/pandas/core/dtypes/dtypes.py), following are the PEP8 issues :

> [Line 941:17](https://github.com/pandas-dev/pandas/blob/5e3179a3c00f0edbfb17fb51904aef0acfae28b7/pandas/core/dtypes/dtypes.py#L941): [E117](https://duckduckgo.com/?q=pep8%20E117) over-indented





 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=h1) Report
> Merging [#25380](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=desc) into [0.24.x](https://codecov.io/gh/pandas-dev/pandas/commit/f0cf03dc2f34855cc95ccd0d5c697bbc29058a08?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/25380/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           0.24.x   #25380      +/-   ##
==========================================
+ Coverage   92.39%   92.39%   +<.01%     
==========================================
  Files         166      166              
  Lines       52409    52412       +3     
==========================================
+ Hits        48424    48428       +4     
+ Misses       3985     3984       -1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.82% <100%> (ø)` | :arrow_up: |
| #single | `42.88% <75%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/dtypes/dtypes.py](https://codecov.io/gh/pandas-dev/pandas/pull/25380/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2R0eXBlcy5weQ==) | `96.12% <100%> (+0.51%)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/25380/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `88.04% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25380?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/25380?src=pr&el=footer). Last update [f0cf03d...5e3179a](https://codecov.io/gh/pandas-dev/pandas/pull/25380?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/25380?src=pr&el=h1) Report
> Merging [#25380](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=desc) into [0.24.x](https://codecov.io/gh/pandas-dev/pandas/commit/f0cf03dc2f34855cc95ccd0d5c697bbc29058a08?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/25380/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           0.24.x   #25380      +/-   ##
==========================================
+ Coverage   92.39%   92.39%   +<.01%     
==========================================
  Files         166      166              
  Lines       52409    52412       +3     
==========================================
+ Hits        48424    48428       +4     
+ Misses       3985     3984       -1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.82% <100%> (ø)` | :arrow_up: |
| #single | `42.88% <75%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/dtypes/dtypes.py](https://codecov.io/gh/pandas-dev/pandas/pull/25380/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2R0eXBlcy5weQ==) | `96.12% <100%> (+0.51%)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/25380/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `88.04% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25380?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/25380?src=pr&el=footer). Last update [f0cf03d...5e3179a](https://codecov.io/gh/pandas-dev/pandas/pull/25380?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
