Fixed black and mypy issue

[WIIASD]

Issue #, if available:

N/A

Description of changes:

Fixing linting issue introduced by this pull request: https://github.com/awslabs/amazon-omics-tools/actions/runs/9845147807/job/27180035884

Testing
The following command succeeded:

ziyangli@amazon-omics-tools % poetry run black --check omics tests
poetry run isort -c omics tests
poetry run flake8 omics tests
poetry run mypy omics --show-error-codes

All done! ✨ 🍰 ✨
28 files would be left unchanged.
Success: no issues found in 15 source files

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[markjschreiber]

LGTM!