Skip to main content
This is a pre-production deployment of Warehouse. Changes made here affect the production instance of PyPI (
Help us improve Python packaging - Donate today!

Implements the null object pattern.

Project Description

Implements the null object pattern.


  • a Null singleton that can be used like None (but is not None and is not equal to None)
  • a NullList that returns Null instead of raising IndexError
  • a NullDict that returns Null instead of raising KeyError
  • a nullify() routine that converts mappings and sequences to the nullified variant
  • an unset singleton for clearing up APIs to distinguish between a keyword argument that is set by the user as None and simply not set by the user

How do I run the tests?

The easiest way would be to extract the source tarball and run:

$ python test/

Change Log


  • will forever be my favourite gotcha of Python packaging
  • PEP8-fied the sources


  • long overdue Python 3 support


  • initial published version


Glued together by Łukasz Langa.

Release History

This version
History Node


History Node


History Node


Download Files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

File Name & Hash SHA256 Hash Help Version File Type Upload Date
(25.6 kB) Copy SHA256 Hash SHA256
Source Mar 5, 2013

Supported By

WebFaction WebFaction Technical Writing Elastic Elastic Search Pingdom Pingdom Monitoring Dyn Dyn DNS Sentry Sentry Error Logging CloudAMQP CloudAMQP RabbitMQ Heroku Heroku PaaS Kabu Creative Kabu Creative UX & Design Fastly Fastly CDN DigiCert DigiCert EV Certificate Rackspace Rackspace Cloud Servers DreamHost DreamHost Log Hosting