ERR: better error message on too large excel sheet
- [ ] closes #26051 
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Hello @anordin95! 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 2019-06-01 12:43:43 UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26080?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/26080/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26080?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##             master   #26080   +/-   ##
=========================================
  Coverage          ?   40.75%           
=========================================
  Files             ?      175           
  Lines             ?    52449           
  Branches          ?        0           
=========================================
  Hits              ?    21373           
  Misses            ?    31076           
  Partials          ?        0
```

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

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26080?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `37.75% <0%> (ø)` | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26080?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/26080?src=pr&el=footer). Last update [190a69e...c5f9db9](https://codecov.io/gh/pandas-dev/pandas/pull/26080?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/26080?src=pr&el=h1) Report
> Merging [#26080](https://codecov.io/gh/pandas-dev/pandas/pull/26080?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/19f693fa70d77c4d52b7ba6eba3afa1496cde605?src=pr&el=desc) will **increase** coverage by `0.07%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26080/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26080?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26080      +/-   ##
==========================================
+ Coverage   91.76%   91.83%   +0.07%     
==========================================
  Files         174      174              
  Lines       50625    50649      +24     
==========================================
+ Hits        46458    46516      +58     
+ Misses       4167     4133      -34
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.37% <100%> (+0.07%)` | :arrow_up: |
| #single | `41.69% <40%> (-0.08%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26080?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/formats/excel.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZXhjZWwucHk=) | `97.44% <100%> (+0.04%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `78.94% <0%> (-10.53%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97% <0%> (-0.12%)` | :arrow_down: |
| [pandas/core/groupby/groupby.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9ncm91cGJ5LnB5) | `97.17% <0%> (-0.06%)` | :arrow_down: |
| [pandas/core/indexes/multi.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9tdWx0aS5weQ==) | `95.62% <0%> (ø)` | :arrow_up: |
| [pandas/core/sparse/scipy\_sparse.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3BhcnNlL3NjaXB5X3NwYXJzZS5weQ==) | `100% <0%> (ø)` | :arrow_up: |
| [pandas/core/groupby/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9fX2luaXRfXy5weQ==) | `100% <0%> (ø)` | :arrow_up: |
| [pandas/core/arrays/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2NhdGVnb3JpY2FsLnB5) | `95.91% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `96.71% <0%> (ø)` | :arrow_up: |
| [pandas/core/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc2VyaWVzLnB5) | `93.61% <0%> (ø)` | :arrow_up: |
| ... and [13 more](https://codecov.io/gh/pandas-dev/pandas/pull/26080/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26080?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/26080?src=pr&el=footer). Last update [19f693f...66f4602](https://codecov.io/gh/pandas-dev/pandas/pull/26080?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 pls merge master and update to comments any suggestions on how to deal with the memoryerror? Perhaps mock / monkeypatch setting the maximum rows & columns to a smaller
size just for that test?

On Mon, May 13, 2019 at 2:18 PM Alexander Nordin <notifications@github.com>
wrote:

> any suggestions on how to deal with the memoryerror?
>
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 how do i go about adding a whatsnew note? @anordin95 look in doc/source/whatsnew/v0.25.0.rst you have a lint error as well

```
./pandas/tests/io/test_excel.py(1220,9): error E265: block comment should start with '# '
Bash exited with code '1'.
``` I pulled master, then rebased onto my branch and have just pushed that, however the rebase had no errors. What's the suggested method to resolve conflicts? looks good, can you merge master as there is a conflict; ping on green. Thank you for all your help :) not sure about the test failure, it looks unrelated to your changes. @anordin95 : the CI failures are fixed. can you merge master. ![image](https://user-images.githubusercontent.com/7705027/58748719-bb84ce00-844a-11e9-84d9-0f14261fb149.png)

I've addressed the requested changes. Could someone provide guidance on how to merge? It appears, I don't have the privilege. One of the maintainers can merge when the CI finishes. Ping when all green thanks @anordin95 