Confused about prepare

Thu Apr 7 18:31:16 EDT 2011

In the code below I use __prepare__ to change the class dictionary so that a tuple is stored in __setitem__(). Since __getitem__() removes the tuple I wasn't expecting any problems, but it seems that __init__ is being retrieved via some other mechanism. Why? Is a copy of the dict being made somewhere? If so, can I change that?
Thanks,
Andrew
class TupleDict(dict):
 '''Stores additional info, but removes it on __getitem__().'''

 def __setitem__(self, key, value):
 print('setting', key, value)
 super(TupleDict, self).__setitem__(key, (value, 'secret'))

 def __getitem__(self, key):
 value = super(TupleDict, self).__getitem__(key)
 print('getting', key, value[0]) # drop secret
 return value[0]
class TupleMeta(type):

 @classmethod
 def __prepare__(metacls, name, bases, **kargs):
 print('in prepare')
 return TupleDict()

 def __new__(cls, name, bases, classdict):
 print('in new')
 return type.__new__(cls, name, bases, classdict)

class C(metaclass=TupleMeta):

 def __init__(self):
 self.a = 1

c = C()
in prepare
setting __module__ __main__
setting __init__ <function __init__ at 0x7f37cbad40d8>
in new
Traceback (most recent call last):
 File ..., line 34, in <module>
 c = C() # TypeError: 'tuple' object is not callable
TypeError: 'tuple' object is not callable

Confused about __prepare__

Confused about prepare