34 lines
769 B
Python
34 lines
769 B
Python
#
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# Copyright (C) 2016 FreeIPA Contributors see COPYING for license
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#
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import weakref
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_cache = weakref.WeakValueDictionary()
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class ListMeta(type):
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def __getitem__(cls, key):
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if not isinstance(key, type):
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raise TypeError("Parameters to generic types must be types. "
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"Got {!r}.".format(key))
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t = ListMeta(
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cls.__name__,
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cls.__bases__,
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{
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'__parameters__': (key,),
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'__init__': cls.__init__,
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}
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)
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return _cache.get(key, t)
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class List(list, metaclass=ListMeta):
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__parameters__ = ()
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def __init__(self, *_args, **_kwargs):
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raise TypeError("Type List cannot be instantiated; use list() instead")
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