bup import-duplicity imports all of the duplicity backups at source-url into bup via bup save -n
save-name. The bup saves will have the same timestamps (via bup save --date) as the original backups.
Because this command operates by restoring each duplicity backup to a temporary directory, the extent to
which the metadata is preserved will depend on the characteristics of the underlying filesystem, whether
or not you run import-duplicity as root (or under fakeroot(1)), etc.
Note that this command will use mkdtemp to create temporary directories, which means that it should
respect any TEMPDIR, TEMP, or TMP environment variable settings. Make sure that the relevant filesystem
has enough space for the largest duplicity backup being imported.
Since all invocations of duplicity use a temporary --archive-dir, import-duplicity should not affect
~/.cache/duplicity.