code: def _get_missing_results(results, dest_dir):
      '''
      Return a list of the filenames specified in the ``results`` argument, which
      are not present in the dest_dir.
      '''
      try:
          present = set(os.listdir(dest_dir))
      except OSError as exc:
          if exc.errno == errno.ENOENT:
              log.debug('pkgbuild.built: dest_dir \'%s\' does not exist', dest_dir)
          elif exc.errno == errno.EACCES:
              log.error('pkgbuilt.built: cannot access dest_dir \'%s\'', dest_dir)
          present = set()
      return sorted(set(results).difference(present)f _get_missing_results(results, dest_dir):
      '''
      Return a list of the filenames specified in the ``results`` argument, which
      are not present in the dest_dir.
      '''
      try:
          present = set(os.listdir(dest_dir))
      except OSError as exc:
          if exc.errno == errno.ENOENT:
              log.debug('pkgbuild.built: dest_dir \'%s\' does not exist', dest_dir)
          elif exc.errno == errno.EACCES:
              log.error('pkgbuilt.built: cannot access dest_dir \'%s\'', dest_dir)
          present = set()
      return sorted(set(results).difference(present))
docs: Return a list of the filenames specified in the ``results`` argument, which
      are not present in the dest_dir.