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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 sleep(self, response=None):
 """ Sleep between retry attempts. This method will respect a server's ``Retry-After`` response header and sleep the duration of the time requested. If that is not present, it will use an exponential backoff. By default, the backoff factor is 0 and this method will return immediately. """


        if response:
            slept = self.sleep_for_retry(response)
            if slept:
                return

        self._sleep_backoff()