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Attribute Tree Construction

Figure 28-1 summarizes the way namespace trees are constructed and populated with names. Generally:

 

Instance attributes are generated by assignments to self attributes in methods. Class attributes are created by statements (assignments) in class statements. Superclass links are made by listing classes in parentheses in a class statement header.

The net result is a tree of attribute namespaces that leads from an instance, to the class it was generated from, to all the superclasses listed in the class header. Python searches upward in this tree, from instances to superclasses, each time you use qualification to fetch an attribute name from an instance object.[66]