'To allow deepcopy to work with OrderedDict.
>>> from copy import deepcopy
>>> a = OrderedDict([(1, 1), (2, 2), (3, 3)])
>>> a[\'test\'] = {}
>>> b = deepcopy(a)
>>> b == a
True
>>> b is a
False
>>> a[\'test\'] is b[\'test\']
False'

def __deepcopy__(self, memo):

    from copy import deepcopy
    return self.__class__(deepcopy(self.items(), memo), self.strict)
