docs: def summarize(group, fs=None, include_source=True):
          """
          Tabulate and write the results of ComparisonBenchmarks to a file or standard out.
          :param str group: name of the comparison group.
          :param fs: file-like object (Optional)
          """
          _line_break = '{0:-<120}\n'.format('')
          tests = sorted(ComparisonBenchmark.groups[group], key=lambda t: getattr(t, 'time_average_seconds'))
          log = StringIO.StringIO()
          log.write('Call statement:\n\n')
          log.write('\t' + tests[0].stmt)
          log.write('\n\n\n')
          fmt = "{0: <8} {1: <35} {2: <12} {3: <15} {4: <15} {5: <14}\n"
          log.write(fmt.format('Rank', 'Function Name', 'Time', '% of Slowest', 'timeit_repeat', 'timeit_number'))
          log.write(_line_break)
          log.write('\n')
  
          for i, t in enumerate(tests):
              func_name = "{}.{}".format(t.classname, t.callable.__name__) if t.classname else t.callable.__name__
              if i == len(tests)-1:
                  time_percent = 'Slowest'
              else:
                  time_percent = "{:.1f}".format(t.time_average_seconds / tests[-1].time_average_seconds * 100)
              log.write(fmt.format(i+1,
                                   func_name,
                                   convert_time_units(t.time_average_seconds),
                                   time_percent,
                                   t.timeit_repeat,
                                   t.timeit_number))
          log.write(_line_break)
  
          if include_source:
              log.write('\n\n\nSource Code:\n')
              log.write(_line_break)
              for test in tests:
                  log.write(test.log.getvalue())
                  log.write(_line_break)
  
          if isinstance(fs, str):
              with open(fs, 'w') as f:
                  f.write(log.getvalue())
  
          elif fs is None:
              print(log.getvalue())
          else:
              try:
                  fs.write(log.getvalue())
              except AttributeError as e:
                  print(e)