ENH: .isnull and .notnull have been added as methods to Index to make this more consistent with the Series API
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15300?src=pr&el=h1) Report
> Merging [#15300](https://codecov.io/gh/pandas-dev/pandas/pull/15300?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/9ddba8dc811184c49d9bc4df5dc97d505345ec23?src=pr&el=desc) will **increase** coverage by `<.01%`.


```diff
@@            Coverage Diff             @@
##           master   #15300      +/-   ##
==========================================
+ Coverage   86.33%   86.33%   +<.01%     
==========================================
  Files         139      139              
  Lines       51149    51157       +8     
==========================================
+ Hits        44157    44165       +8     
  Misses       6992     6992
```


| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/15300?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/tseries/base.py](https://codecov.io/gh/pandas-dev/pandas/compare/9ddba8dc811184c49d9bc4df5dc97d505345ec23...8c35656f7911e1aaa5d11a3902939f29d722c34a?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvYmFzZS5weQ==) | `96.59% <100%> (ø)` | :white_check_mark: |
| [pandas/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/compare/9ddba8dc811184c49d9bc4df5dc97d505345ec23...8c35656f7911e1aaa5d11a3902939f29d722c34a?src=pr&el=tree#diff-cGFuZGFzL2luZGV4ZXMvYmFzZS5weQ==) | `96.17% <100%> (+0.01%)` | :white_check_mark: |
| [pandas/indexes/category.py](https://codecov.io/gh/pandas-dev/pandas/compare/9ddba8dc811184c49d9bc4df5dc97d505345ec23...8c35656f7911e1aaa5d11a3902939f29d722c34a?src=pr&el=tree#diff-cGFuZGFzL2luZGV4ZXMvY2F0ZWdvcnkucHk=) | `98.57% <100%> (ø)` | :white_check_mark: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15300?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/15300?src=pr&el=footer). Last update [9ddba8d...8c35656](https://codecov.io/gh/pandas-dev/pandas/compare/9ddba8dc811184c49d9bc4df5dc97d505345ec23...8c35656f7911e1aaa5d11a3902939f29d722c34a?el=footer&src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).