Modern Python Standard Library Cookbook

Bunch

Python is very good at shapeshifting objects. Each instance can have its own attributes and it's absolutely legal to add/remove the attributes of an object at runtime.

Once in a while, our code needs to deal with data of unknown shapes. For example, in the case of a user-submitted data, we might not know which fields the user is providing; maybe some of our users have a first name, some have a surname, and some have one or more middle name fields.

If we are not processing this data ourselves, but are just providing it to some other function, we really don't care about the shape of the data; as long as our objects have those attributes, we are fine.

A very common case is when working with protocols, if you are an HTTP server, you might ...