implement ABCInterval
Avoid python-space import in lib

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

need test in pandas/tests/dtypes/test_generic.py # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19367?src=pr&el=h1) Report
> Merging [#19367](https://codecov.io/gh/pandas-dev/pandas/pull/19367?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/7202635c9332b2b510f3f32cb1e97e3268edc61f?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/19367/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/19367?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #19367      +/-   ##
==========================================
- Coverage   91.61%    91.6%   -0.02%     
==========================================
  Files         150      150              
  Lines       48677    48685       +8     
==========================================
+ Hits        44595    44596       +1     
- Misses       4082     4089       +7
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.97% <100%> (-0.02%)` | :arrow_down: |
| #single | `41.72% <100%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/19367?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/dtypes/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/19367/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2dlbmVyaWMucHk=) | `100% <100%> (ø)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/19367/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `83.83% <0%> (-0.62%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19367?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/19367?src=pr&el=footer). Last update [7202635...6162585](https://codecov.io/gh/pandas-dev/pandas/pull/19367?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks!