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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):
 """Flushes the event file to disk."""

        if self._num_outstanding_events == 0 or self._recordio_writer is None:
            return
        self._recordio_writer.flush()
        if self._logger is not None:
            self._logger.info('wrote %d %s to disk', self._num_outstanding_events,
                              'event' if self._num_outstanding_events == 1 else 'events')
        self._num_outstanding_events = 0