What is the difference between old style and new style classes in Python?

Question

What is the difference between old style and new style classes in Python? When should I use one or the other?

Answer 1

New-style classes inherit from object and must be written as such in Python 2.2 onwards (i.e. class Classname(object): instead of class Classname:). The core change is to unify types and classes, and the nice side-effect of this is that it allows you to inherit from built-in types.

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