dedupe fedora silverblue results in AssertionError

[lizelive]

[lizelive@fedora ~]$ sudo podman run --rm -it --device /dev/sda2 --privileged -v /var/home/lizelive/.local/share/containers/storage/:/mnt docker.io/laks/dduper dduper --device /dev/sda2 --dir /mnt --analyze --recurse
Traceback (most recent call last):
  File "/usr/sbin/dduper", line 575, in <module>
    main(results)
  File "/usr/sbin/dduper", line 465, in main
    dedupe_dir(results.dir_path, results.dry_run, results.recurse)
  File "/usr/sbin/dduper", line 456, in dedupe_dir
    dedupe_files(file_list, dry_run)
  File "/usr/sbin/dduper", line 410, in dedupe_files
    ret = do_dedupe(src_file, dst_file, dry_run)
  File "/usr/sbin/dduper", line 224, in do_dedupe
    assert len(out1) != 0
AssertionError

what is the correct way to dedupe?

related to #48