freezer

hi i recently install the freezer api and i have problem with using it if run this command: freezer-agent --debug --action backup --nova-inst-id a143d11d-fa27-4716-9795-e03b4e601df4 --storage local --container /tmp/ali --backup-name test --mode nova --engine nova --no-incremental true --log-file a.log --consistency-check and freezer api doesn't work current and error with: Engine error: a bytes-like object is required, not 'str' Engine error: Forced stop Adn attach the log please help me ! thank you for attention