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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 flush(self):
 """Force a flush."""

    if not self.items:
      return

    retry = 0
    options = {"deadline": DATASTORE_DEADLINE}
    while retry <= self.__timeout_retries:
      try:
        self.__flush_function(self.items, options)
        self.clear()
        break
      except db.Timeout, e:
        logging.warning(e)
        logging.warning("Flushing '%s' timed out. Will retry for the %s time.",
                        self, retry)
        retry += 1
        options["deadline"] *= 2
      except apiproxy_errors.RequestTooLargeError:
        self._log_largest_items()
        raise
    else:
      raise