CLN: remove compat.iterkeys
- [x] xref #25725

Removes ``compat.iterkeys``.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26081?src=pr&el=h1) Report
> :exclamation: No coverage uploaded for pull request base (`master@190a69e`). [Click here to learn what that means](https://docs.codecov.io/docs/error-reference#section-missing-base-commit).
> The diff coverage is `0%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26081/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26081?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##             master   #26081   +/-   ##
=========================================
  Coverage          ?   40.75%           
=========================================
  Files             ?      175           
  Lines             ?    52442           
  Branches          ?        0           
=========================================
  Hits              ?    21372           
  Misses            ?    31070           
  Partials          ?        0
```

| Flag | Coverage Δ | |
|---|---|---|
| #single | `40.75% <0%> (?)` | |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26081?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/compat/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/26081/diff?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fX2luaXRfXy5weQ==) | `82.75% <ø> (ø)` | |
| [pandas/core/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/26081/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYmFzZS5weQ==) | `33.85% <0%> (ø)` | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26081?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/26081?src=pr&el=footer). Last update [190a69e...72000d0](https://codecov.io/gh/pandas-dev/pandas/pull/26081?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/26081?src=pr&el=h1) Report
> Merging [#26081](https://codecov.io/gh/pandas-dev/pandas/pull/26081?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/d9c9e2f01ab53de2ba4031367bc570ce66dac374?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/26081/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26081?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26081      +/-   ##
==========================================
- Coverage   91.95%   91.94%   -0.01%     
==========================================
  Files         175      175              
  Lines       52427    52425       -2     
==========================================
- Hits        48208    48203       -5     
- Misses       4219     4222       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.5% <100%> (-0.01%)` | :arrow_down: |
| #single | `40.72% <0%> (-0.15%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26081?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/compat/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/26081/diff?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9fX2luaXRfXy5weQ==) | `92.72% <ø> (-0.26%)` | :arrow_down: |
| [pandas/core/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/26081/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYmFzZS5weQ==) | `97.99% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26081/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `75% <0%> (-12.5%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26081/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.79% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26081/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.71% <0%> (+0.1%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26081?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/26081?src=pr&el=footer). Last update [d9c9e2f...48c6175](https://codecov.io/gh/pandas-dev/pandas/pull/26081?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Hello @topper-123! 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 2019-04-15 08:20:54 UTC Thanks @mroeschke , I was not certain if the error was something I wasnt catching locally. @topper-123 : If you can address the merge conflicts that stemmed from merging your other PR, this should be good to go. Rebased. thanks @pep8speaks 