code: def diff(
          cobertura_file1, cobertura_file2,
          color, format, output, source1, source2,
          source_prefix1, source_prefix2, source):
      
      cobertura1 = Cobertura(
          cobertura_file1,
          source=source1,
          source_prefix=source_prefix1
      )
      cobertura2 = Cobertura(
          cobertura_file2,
          source=source2,
          source_prefix=source_prefix2
      )
  
      Reporter = delta_reporters[format]
      reporter_args = [cobertura1, cobertura2]
      reporter_kwargs = {'show_source': source}
  
      isatty = True if output is None else output.isatty()
  
      if format == 'text':
          color = isatty if color is None else color is True
          reporter_kwargs['color'] = color
  
      reporter = Reporter(*reporter_args, **reporter_kwargs)
      report = reporter.generate()
  
      if not isinstance(report, bytes):
          report = report.encode('utf-8')
  
      click.echo(report, file=output, nl=isatty, color=color)
  
      exit_code = get_exit_code(reporter.differ, source)
      raise SystemExit(exit_code)
docs: compare coverage of two Cobertura reports