PPA migrator utility fails with the following error:
~# ppa-transfer generate-migration-list config.ini [ERROR] parallels.plesks_migrator.migrator || ABORT (by exception): fetch info from PPA [ERROR] parallels || Unexpected error: 'invalid arguments passed to constructor', migration is aborted. See the traceback above for more information.
The issue is caused by several unsuccessful migration attempts, as a result
migration-session directory contains invalid data.
To fix the issue it is needed to remove all the files from
rm -r /etc/ppa-migrator/migration-session