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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 _get_ordered_access_keys(self):
        "Return ordered access keys for inspection. Used for testing."
        self.access_log_lock.acquire()
        r = [e.key for e in self.access_log if e.is_valid]
        self.access_log_lock.release()

        return r