重复“CollectionsError：未找到备份链”

我正在使用 duplicity 0.7.06 进行备份，使用 0.7.17 来恢复 duplicity 备份。但是在尝试从中还原目录时出现错误“未找到备份链”。

我不确定那个错误意味着什么。

备份是这样进行的（并且没有错误）：

duplicity --no-encryption --full-if-older-than 10D /path/to/dir s3+http://my-s3-bucket/duplicity/dir

如果我列出它们，我可以看到重复档案：

~$ s3cmd ls s3://my-s3-bucket/duplicity/dir/
2019-05-12 15:51     19505   s3://my-s3-bucket/duplicity/dir/duplicity-full-signatures.20190512T155147Z.sigtar.gz
2019-05-12 15:51       724   s3://my-s3-bucket/duplicity/dir/duplicity-full.20190512T155147Z.manifest
2019-05-12 15:51    728333   s3://my-s3-bucket/duplicity/dir/duplicity-full.20190512T155147Z.vol1.difftar.gz

我正在尝试像这样恢复它：

duplicity --file-to-restore path/to/dir s3+http://my-s3-bucket/duplicity /home/restored/dir

我得到的错误是：

duplicity 0.7.17 (February 26, 2018)
Args: /usr/bin/duplicity --file-to-restore path/to/dir s3+http://my-s3-bucket/duplicity /home/restored/dir
Linux machinename 4.15.0-48-generic #51-Ubuntu SMP Wed Apr 3 08:28:49 UTC 2019 x86_64 x86_64
/usr/bin/python2 2.7.15rc1 (default, Nov 12 2018, 14:31:15) 
[GCC 7.3.0]
================================================================================
Using temporary directory /tmp/duplicity-Zu29z3-tempdir
Temp has 30699757568 available, backup will use approx 272629760.
Local and Remote metadata are synchronized, no sync needed.
Last full backup date: none
Traceback (innermost last):
  File "/usr/bin/duplicity", line 1555, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1541, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1393, in main
    do_backup(action)
  File "/usr/bin/duplicity", line 1472, in do_backup
    restore(col_stats)
  File "/usr/bin/duplicity", line 728, in restore
    restore_get_patched_rop_iter(col_stats)):
  File "/usr/bin/duplicity", line 750, in restore_get_patched_rop_iter
    backup_chain = col_stats.get_backup_chain_at_time(time)
  File "/usr/lib/python2.7/dist-packages/duplicity/collections.py", line 974, in get_backup_chain_at_time
    raise CollectionsError("No backup chains found")
 CollectionsError: No backup chains found