Track 11 · Lesson 5 of 12

Class attributes, classmethods and staticmethods

Share data across all objects with class attributes, avoid the shared-mutable trap, and add alternate constructors with classmethod.

You will be able to

• Tell class attributes (shared by every object) from instance attributes (one per object)
• Use a class attribute for constants and for counting objects
• Recognise and fix the shared mutable class attribute bug
• Write a classmethod that builds objects from another format (an alternate constructor)
• Use a staticmethod for a helper that belongs with the class but needs no object