DEPR: Deprecate box kwarg for to_timedelta and to_datetime
- [x] closes #24416
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

There are still some tests that are failing on Travis, but they appear to be unrelated.  I'll see what CI returns for the PR and address any tests that continue to fail that might be due to the changes here.

You mean assert that the warning is raised in those cases? yes need to eliminate all warnings from the test suite - either catch them or remove the box parameter (prob the former is ok here) # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=h1) Report
> Merging [#24486](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/aeff38d3301d4d31650f6624304259d0dfdbd69b?src=pr&el=desc) will **decrease** coverage by `49.25%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24486/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=tree)

```diff
@@             Coverage Diff             @@
##           master   #24486       +/-   ##
===========================================
- Coverage   92.31%   43.05%   -49.26%     
===========================================
  Files         166      166               
  Lines       52335    52339        +4     
===========================================
- Hits        48313    22535    -25778     
- Misses       4022    29804    +25782
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `?` | |
| #single | `43.05% <100%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/tools/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvdG9vbHMvdGltZWRlbHRhcy5weQ==) | `67.92% <100%> (-30.12%)` | :arrow_down: |
| [pandas/core/tools/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvdG9vbHMvZGF0ZXRpbWVzLnB5) | `34.51% <100%> (-51.25%)` | :arrow_down: |
| [pandas/io/formats/latex.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvbGF0ZXgucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/core/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY2F0ZWdvcmljYWwucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/io/sas/sas\_constants.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3Nhcy9zYXNfY29uc3RhbnRzLnB5) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/tseries/plotting.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvcGxvdHRpbmcucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/tseries/converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvY29udmVydGVyLnB5) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/io/formats/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvaHRtbC5weQ==) | `0% <0%> (-98.65%)` | :arrow_down: |
| [pandas/core/groupby/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9jYXRlZ29yaWNhbC5weQ==) | `0% <0%> (-95.46%)` | :arrow_down: |
| [pandas/io/sas/sas7bdat.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3Nhcy9zYXM3YmRhdC5weQ==) | `0% <0%> (-91.17%)` | :arrow_down: |
| ... and [126 more](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24486?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/24486?src=pr&el=footer). Last update [aeff38d...5b84d9c](https://codecov.io/gh/pandas-dev/pandas/pull/24486?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/24486?src=pr&el=h1) Report
> Merging [#24486](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/26d991fc4e568432c3264151265c0a3ea9a6f133?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/24486/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24486      +/-   ##
==========================================
- Coverage   91.28%   91.27%   -0.01%     
==========================================
  Files         173      173              
  Lines       52965    52969       +4     
==========================================
+ Hits        48348    48350       +2     
- Misses       4617     4619       +2
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.85% <100%> (-0.01%)` | :arrow_down: |
| #single | `41.74% <57.14%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/parsers.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3BhcnNlcnMucHk=) | `95.34% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZWxpa2UucHk=) | `98.52% <100%> (ø)` | :arrow_up: |
| [pandas/core/tools/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvdG9vbHMvdGltZWRlbHRhcy5weQ==) | `98.14% <100%> (+0.07%)` | :arrow_up: |
| [pandas/core/tools/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvdG9vbHMvZGF0ZXRpbWVzLnB5) | `84.63% <100%> (-0.5%)` | :arrow_down: |
| [pandas/core/dtypes/cast.py](https://codecov.io/gh/pandas-dev/pandas/pull/24486/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2Nhc3QucHk=) | `88.16% <100%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24486?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/24486?src=pr&el=footer). Last update [26d991f...4d6e0d3](https://codecov.io/gh/pandas-dev/pandas/pull/24486?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Would it make sense to transition all of the internal uses of box here as well? > Would it make sense to transition all of the internal uses of box here as well?

yep.  Hello @cbertinato! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:

















There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2019-03-12 15:23:12 UTC some lint issues and needs a rebase @cbertinato this is looking close, can you see if get passing All green! All green. thanks @cbertinato nice patch!