cleaning up old links that are no longer relevant

mattmakai · mattmakai · commit 2d8f66589633 · 2021-01-27T05:59:36.000-05:00
diff --git a/content/pages/01-introduction/02-python-programming-language.markdown b/content/pages/01-introduction/02-python-programming-language.markdown
@@ -108,9 +108,6 @@ Dictionary comprehension:
 * Armin Roacher presented [things you didn't know about Python](https://speakerdeck.com/mitsuhiko/didntknow)
   at PyCon South Africa in 2012.
 
-* [Writing idiomatic Python](http://www.jeffknupp.com/blog/2012/10/04/writing-idiomatic-python/)
-  is a guide for writing Pythonic code.
-
 
 ### Python ecosystem resources
 There's an entire page on [best Python resources](/best-python-resources.html)
diff --git a/content/pages/03-data/10-no-sql-datastore.markdown b/content/pages/03-data/10-no-sql-datastore.markdown
@@ -189,10 +189,6 @@ representing a person could have a property of "female" or "male".
 * [CAP Theorem overview](http://natishalom.typepad.com/nati_shaloms_blog/2010/10/nocap.html)
   presents the basic constraints all databases must trade off in operation.
 
-* This post on [What is a NoSQL database? Learn By Writing One in Python](http://jeffknupp.com/blog/2014/09/01/what-is-a-nosql-database-learn-by-writing-one-in-python/)
-  is a detailed article that breaks the mystique behind what some forms
-  of NoSQL databases are doing under the covers.
-
 * The [CAP Theorem series](http://blog.thislongrun.com/2015/03/the-cap-theorem-series.html)
   explains concepts related to NoSQL such as what is ACID compared to CAP, CP
   versus CA and high availability in large scale deployments.
diff --git a/content/pages/04-web-development/01-web-frameworks.markdown b/content/pages/04-web-development/01-web-frameworks.markdown
@@ -150,10 +150,6 @@ frameworks, templating engines and
   I agree although I've found sessions and database ORMs to be a helpful
   part of a framework when done well.
 
-* "[What is a web framework?](http://www.jeffknupp.com/blog/2014/03/03/what-is-a-web-framework/)"
-  is an in-depth explanation of what web frameworks are and their relation
-  to web servers.
-
 * [Django vs Flask vs Pyramid: Choosing a Python Web Framework](https://www.airpair.com/python/posts/django-flask-pyramid)
   contains background information and code comparisons for similar
   web applications built in these three big Python frameworks.
diff --git a/content/pages/04-web-development/02-django.markdown b/content/pages/04-web-development/02-django.markdown
@@ -50,11 +50,6 @@ groups such as [Django District](http://www.meetup.com/django-district/),
 [San Francisco Django](http://www.meetup.com/The-San-Francisco-Django-Meetup-Group/) 
 so new developers can get help when they are stuck.
 
-There's some debate on whether 
-[learning Python by using Django is a bad idea](http://www.jeffknupp.com/blog/2012/12/11/learning-python-via-django-considered-harmful/). 
-However, that criticism is invalid if you take the time to learn the Python
-syntax and language semantics first before diving into web development.
-
 
 ## Django books and tutorials
 There are a slew of free or low cost resources out there for Django. Make
diff --git a/content/pages/04-web-development/03-flask.markdown b/content/pages/04-web-development/03-flask.markdown
@@ -205,9 +205,6 @@ combined with the example real-world projects listed in the next section.
   is a killer Flask tutorial with all the code needed to create a
   web app that can dial phones and receive inbound calls.
 
-* Jeff Knupp provides some solid advice on how to 
-  [productionize a Flask app](http://www.jeffknupp.com/blog/2014/01/29/productionizing-a-flask-application/).
-
 * If you're looking for a fun tutorial with Flask and WebSockets, check out
   my blog post on creating 
   [Choose Your Own Adventure Presentations with Reveal.js, Python and WebSockets](https://www.twilio.com/blog/2014/11/choose-your-own-adventure-presentations-with-reveal-js-python-and-websockets.html).
diff --git a/content/pages/04-web-development/36-unit-testing.markdown b/content/pages/04-web-development/36-unit-testing.markdown
@@ -70,10 +70,6 @@ Python-specific applications.
   is a detailed tutorial for using the nose test runner for ensuring a
   Flask application is working properly.
 
-* [Understanding unit testing](https://jeffknupp.com/blog/2013/12/09/improve-your-python-understanding-unit-testing/)
-  explains why testing is important and shows how to do it effectively in
-  your applications.
-
 * [Unit testing with Python](http://www.drdobbs.com/testing/unit-testing-with-python/240165163)
   provides a high-level overview of testing and has diagrams to demonstrate
   what's going on in the testing cycle.
diff --git a/content/pages/examples/django/django-extensions-plug-ins.markdown b/content/pages/examples/django/django-extensions-plug-ins.markdown
@@ -592,6 +592,22 @@ under the
 [MIT license](https://github.com/yunojuno/django-user-visit/blob/master/LICENSE).
 
 
+### django-version-checks
+[django-version-checks](https://github.com/adamchainz/django-version-checks)
+([PyPI package](https://pypi.org/project/django-version-checks/))
+is a code library to ensure external system dependencies match
+desired versions. For example, a specific version of 
+[PostgreSQL](/postgresql.html) or [MySQL](/mysql.html) as your database
+backend. This is different from using `pip` and a `requirements.txt` file,
+because those are Python dependencies, rather than system-wide software.
+The 
+[introductory blog post](https://adamj.eu/tech/2020/12/14/introducing-django-version-checks/)
+for the project has some good reasons why these external dependencies
+can cause problems if they vary from the expected versions.
+
+django-version-checks is provided as open source under the
+[MIT license](https://github.com/adamchainz/django-version-checks/blob/master/LICENSE).
+
 ### django-webshell
 [django-webshell](https://github.com/onrik/django-webshell) is an extension
 for executing arbitrary code in the 
