Name mangling occurs during the evaluation of a class
statement. In the case of Bar
, the __cache
attribute is not defined as part of the class, but rather added to a specific object after the fact.
(Actually, that may not be entirely correct. Name mangling may occur during the evaluation of the __new__
method; I do not know. But regardless, your __cache
is added explicitly to a single object, not added by the class code.)