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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 _prepare_results(self, results):
 """ Called in _collection to prepare results from redis before returning them. """

        if self._instances:
            results = self._to_instances(results)
        else:
            results = list(results)

        # cache the len for future use
        self._len = len(results)

        return results