Attribute reference design

[chamalulu]

Hello.
I think I'm aware of how attribute access is resolved in python. When
referencing a class instance attribute which is not defined in the
scope of the instance, Python looks for a class attribute with the
same name. (For assignment or deletion this is not the case,
thankfully.)
I've been trying to understand why? What is the reason behind, or
practical purpose of, this design decision? Anyone, please enlighten
me.

/Henrik