def __init__(self, *args, **kwargs):
        '''Like with the ordinary dict: from a mapping, from an iterable
        of (key, value) pairs, or from keyword arguments.'''
        dict.__init__(self, *args, **kwargs)
        self._sorted_keys = sorted(dict.iterkeys(self))
Like with the ordinary dict: from a mapping, from an iterable
        of (key, value) pairs, or from keyword arguments.
recipes/Python/576998_Sorted_dictionary/recipe-576998.py