a zillion flakes
ugh.  No doubt I missed a bunch...

There are a handful of things, especially in parsers.pyx where "comments" look like commented-out code that should be either deleted or otherwise handled.  I'm declaring that [SEP](http://hitchhikers.wikia.com/wiki/Somebody_Else%27s_Problem_field).
fine modulo @jorisvandenbossche comment.
 > ugh. No doubt I missed a bunch...

its pretty easy to run this locally.  # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=h1) Report
> Merging [#18046](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/c65a0f554b0381ac3f50762050a56bcff188ffa1?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18046/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18046      +/-   ##
==========================================
- Coverage   91.24%   91.23%   -0.02%     
==========================================
  Files         163      163              
  Lines       50114    50114              
==========================================
- Hits        45729    45720       -9     
- Misses       4385     4394       +9
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.04% <ø> (ø)` | :arrow_up: |
| #single | `40.24% <ø> (-0.06%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.75% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18046?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/18046?src=pr&el=footer). Last update [c65a0f5...b693180](https://codecov.io/gh/pandas-dev/pandas/pull/18046?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/18046?src=pr&el=h1) Report
> Merging [#18046](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/881ee30b443f8b9651068b819ecd43adca5789b5?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/18046/graphs/tree.svg?src=pr&token=eZ4WkYLtcO&width=650&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18046      +/-   ##
==========================================
- Coverage   91.25%   91.23%   -0.02%     
==========================================
  Files         163      163              
  Lines       50115    50115              
==========================================
- Hits        45730    45721       -9     
- Misses       4385     4394       +9
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.04% <100%> (ø)` | :arrow_up: |
| #single | `40.23% <100%> (-0.06%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/tseries/frequencies.py](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvZnJlcXVlbmNpZXMucHk=) | `96% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.75% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18046?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/18046?src=pr&el=footer). Last update [881ee30...e49a004](https://codecov.io/gh/pandas-dev/pandas/pull/18046?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 We may need to re-think this strategy if we can't close this quickly.  This touches so many things that it's going to need to be rebased a ton. Fixed up remaining complaints locally, with the exception of Timedelta.  Didn't want to cause merge conflicts with #17937. @jbrockmendel 

The simplest method is to add 2 sections in lint.sh, one with the 'fixed' ones and one with the todo.

you leave the todo with the existing flake checks, and gradually add files to the fixed.

The you can change 1 file at a time (or a small number).

we did this for the entire code base; if you do it piece by piece its easy. In principle this can be merged quickly, as you prefer (I think it are mainly your PRs that will have merge conflicts) ok since we merged the nattype, this needs a rebase (upside is it should be good to go after) :>

ping when green. thanks!