code: def _save_sorted_results(self, run_stats, scores, image_count, filename):
      
      with open(filename, 'w') as f:
        writer = csv.writer(f)
        writer.writerow(['SubmissionID', 'ExternalTeamId', 'Score',
                         'MedianTime', 'ImageCount'])
  
        def get_second(x):
          """Returns second entry of a list/tuple"""
          return x[1]
        for s_id, score in sorted(iteritems(scores),
                                  key=get_second, reverse=True):
          external_id = self.submissions.get_external_id(s_id)
          stat = run_stats.get(
              s_id, collections.defaultdict(lambda: float('NaN')))
          writer.writerow([s_id, external_id, score,
                           stat['median_eval_time'],
                           image_count[s_id]])
docs: Saves sorted (by score) results of the evaluation.
  
      Args:
        run_stats: dictionary with runtime statistics for submissions,
          can be generated by WorkPiecesBase.compute_work_statistics
        scores: dictionary mapping submission ids to scores
        image_count: dictionary with number of images processed by submission
        filename: output filename