small update to docs hide cell

[lwasser]

closes #1194
In the documentation, the code to hide cells currently returns an error where it can't find the TagRemoveProcessor object. A resolution was proposed in this issue to register the processor prior to calling it.

Further the example is missing code to export the object to a file which many users may need to do! This pr simply fixes the code sample. @yuvipanda I'm very open to making any changes and testing the locally! I am running the most current released version of nbconvert. i built the docs locally and ran into a small issue:

(nbconvert) CIRES-EL-LM-020:docs leahwasser$ make html
sphinx-build -b html -d build/doctrees   source build/html
Running Sphinx v3.5.4
loading intersphinx inventory from https://docs.python.org/3.6/objects.inv...
loading intersphinx inventory from http://jinja.pocoo.org/docs/dev/objects.inv...
loading intersphinx inventory from https://nbformat.readthedocs.io/en/latest/objects.inv...
intersphinx inventory has moved: http://jinja.pocoo.org/docs/dev/objects.inv -> https://jinja.palletsprojects.com/en/master/objects.inv
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 22 source files that are out of date
updating environment: [new config] 22 added, 0 changed, 0 removed
reading sources... [ 86%] nbconvert_library                                            
Notebook error:
NoSuchKernel in nbconvert_library.ipynb:
No such kernel named python3

i'm not sure if that is related to my environment install but the docs that i modified should not actually cause any build issues. let's see what CI has to say.

UPDATE: i was able to fix this by installing notebook in my nbconvert dev envt and rerunning the notebook figuring perhaps it would then find the right kernel and add it to the notebook metadata. docs are now building nicely locally. i'll see if that URL fix also solves the CI issues.

[lwasser]

CURRENTLY FAILING - but because of a bad url in nbconvert_library.ipynb - i believe the URL may be this instead so implemented that and will watch ci for happy green lights!
https://jakevdp.github.io/downloads/notebooks/XKCD_plots.ipynb

[lwasser]

It looks like circleci wants pip to be installed with the envt. i'm happy to add it. will let it build first and revisit.

[lwasser]

Huh - ok adding pip sped up t he build but now i'm getting this

`Warning, treated as error:
/root/checkout/nbconvert/exporters/exporter.py:docstring of nbconvert.exporters.exporter.Exporter.register_preprocessor:8:more than one target found for 'any' cross-reference 'Preprocessor': could be :py:class:`nbconvert.preprocessors.Preprocessor` or :py:class:`nbconvert.preprocessors.base.Preprocessor`

i see the docstring issue but am not sure which Preprocessor is correct. docs are building fine locally. happy to fix this too if i know which preprocessor to call there or how to fix this?

[lwasser]

ok @yuvipanda i may need your input on the docstring issue. it's unrelated to this PR but i'm happy to fix it if it's small with some direction. i'm also happy to undo the pip add. it just seemed to make circleci happier.

[yuvipanda]

Ah that looks unrelated, @lwasser. Can you remove the pip related change, and I'll just merge?

[lwasser]

@yuvipanda no problem! it's removed now!

[yuvipanda]

Thanks, @lwasser. I'm digging through the test failures in #1569

[yuvipanda]

@lwasser just noticed a small typo I think, sorry didn't catch this the first time around

[lwasser]

@yuvipanda no worries - my mistake. typo is fixed. let me know what else you need! that pip install did seem to help CI out speedwise!

[yuvipanda]

@lwasser \oo/ nah, this is good - I've merged it! Do you want to try another PR with the pip changes to see if we can unbreak the CI?

[lwasser]

sure thing! i am in meetings for the next 1.5ish hours and can do it after! i think that docstring issue also needs to be addressed. it's only a warning but i think it's making CI unhappy. more in a bit!

[yuvipanda]

@lwasser yep! I might head to bed anyway (still stuck in india), but will look when i wake up :)

[lwasser]

oh gosh. are you unable to get a flight back @yuvipanda ? get some sleep!

[yuvipanda]

@lwasser yeah, long story, but i came here for 6 weeks in feb 2020 and here I am still...

[lwasser]

Oh gosh yuvi! You've been there for that long? I hope uve been able to stay safe as it doesn't sound like vaccines are available there like they are here. Sent from my Verizon, Samsung Galaxy smartphone Get Outlook for Android<https://aka.ms/AAb9ysg>

…

________________________________ From: Yuvi Panda ***@***.***> Sent: Friday, May 14, 2021 2:35:07 AM To: jupyter/nbconvert ***@***.***> Cc: Leah Wasser <[email protected]>; Mention ***@***.***> Subject: Re: [jupyter/nbconvert] small update to docs hide cell (#1567) @lwasser<https://github.com/lwasser> yeah, long story, but i came here for 6 weeks in feb 2020 and here I am still... — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#1567 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AB2LPKV2HRWSSTKTDNYGO5LTNTODXANCNFSM44ZRPPGA>.

[yuvipanda]

@lwasser yeah it's a total mess :( Hopefully I can come back before end of the year...