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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 columns_dataset(self):
 """ Implement high level cache system for columns and dataset. """

        cache = self.cache
        cache_key = 'columns_dataset'
        if cache_key not in cache:
            columns_dataset = super(CachedModelVectorBuilder, self
                                    ).columns_dataset
            cache[cache_key] = columns_dataset
            self.cache = cache
        return cache[cache_key]