53     def __setitem__(cls, key, value):  argument
57             key += MUTABLE
58         setattr(cls, key, value)
60     def __getmutable__(cls, key, readonly=False):  argument
61         nkey = key + MUTABLE
72             print("Warning: Doing a copy because %s is a mutable type." % key, file=cls.__warn__)
82     def __getreadonly__(cls, key, default=__getmarker__):  argument
86         return cls.__getitem__(key, default, True)
88     def __getitem__(cls, key, default=__getmarker__, readonly=False):  argument
91                 value = getattr(cls, key)
93                 value = cls.__getmutable__(key, readonly)
97                 raise AttributeError("key %s does not exist." % key)
106     def __delitem__(cls, key):  argument
107         cls.__setitem__(key, cls.__marker__)
109     def __revertitem__(cls, key):  argument
110         if key not in cls.__dict__:
111             key += MUTABLE
112         delattr(cls, key)
114     def __contains__(cls, key):  argument
115         return cls.has_key(key)
117     def has_key(cls, key):  argument
118         value = cls.__getreadonly__(key, cls.__marker__)
124         for key in dir(cls):
125             if key.startswith("__"):
128             if key.endswith(MUTABLE):
129                 key = key[:-len(MUTABLE)]
132                 yield key
136                     value = cls.__getreadonly__(key)
138                     value = cls[key]
145                 yield (key, value)