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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def load(cls, cache_key, deserializer, key_attr):
 """ Load the persisted cache and return a new instance of this class. """

        items = unitdata.kv().get(cache_key) or []
        return cls(cache_key,
                   [deserializer(item) for item in items],
                   key_attr)