code: def _OpenFilesForRead(self, metadata_value_pairs, token):
      
      aff4_paths = [
          result.AFF4Path(metadata.client_urn)
          for metadata, result in metadata_value_pairs
      ]
      fds = aff4.FACTORY.MultiOpen(aff4_paths, mode="r", token=token)
      fds_dict = dict([(fd.urn, fd) for fd in fds])
      return fds_dict
docs: Open files all at once if necessary.