which "dictionary with attribute-style access"?

[Andreas Balogh]

Hello,

googling I found several ways of implementing a "dictionary with 
attribute-style access".

1. ActiveState cookbook: http://code.activestate.com/recipes/473786/

2. ActiveState cookbook: 
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/361668

3. web2py codebase: Storage(dict)

I enclosed the three implementations below.

My question to the Python specialists: which one is the most correct?
Are there restrictions with regards to pickling or copy()?
Which one should I choose?

Regards, Andreas

-- 
Andreas Balogh
baloand (at) gmail.com

-----------------------------------------------------------------------
class AttrDict(dict):
     """ comments removed """
     """A dictionary with attribute-style access. It maps attribute 
access to the real dictionary.  """
	def __init__(self, init={}):
		dict.__init__(self, init)

	def __getstate__(self):
		return self.__dict__.items()

	def __setstate__(self, items):
		for key, val in items:
			self.__dict__[key] = val

	def __repr__(self):
		return "%s(%s)" % (self.__class__.__name__, dict.__repr__(self))

	def __setitem__(self, key, value):
		return super(AttrDict, self).__setitem__(key, value)

	def __getitem__(self, name):
		return super(AttrDict, self).__getitem__(name)

	def __delitem__(self, name):
		return super(AttrDict, self).__delitem__(name)

	__getattr__ = __getitem__
	__setattr__ = __setitem__

	def copy(self):
		ch = AttrDict(self)
		return ch
-----------------------------------------------------------------------
class attrdict(dict):
     """ comments removed """
     def __init__(self, *args, **kwargs):
         dict.__init__(self, *args, **kwargs)
         self.__dict__ = self
-----------------------------------------------------------------------
class Storage(dict):
     """ comments removed """
     def __getattr__(self, key):
         try:
             return self[key]
         except KeyError, k:
             return None

     def __setattr__(self, key, value):
         self[key] = value

     def __delattr__(self, key):
         try:
             del self[key]
         except KeyError, k:
             raise AttributeError, k

     def __repr__(self):
         return '<Storage ' + dict.__repr__(self) + '>'

     def __getstate__(self):
         return dict(self)

     def __setstate__(self, value):
         for (k, v) in value.items():
             self[k] = v