$ pre-commit run -a
...
Docker Format............................................................Failed
- hook id: hadolint
- exit code: 1

python/examples/minimal_build/Dockerfile.fedora:20 DL3040 warning: `dnf clean all` missing after dnf command.
python/examples/minimal_build/Dockerfile.fedora:20 DL3041 warning: Specify version with `dnf install -y <package>-<version>`.
python/examples/minimal_build/Dockerfile.fedora:32 DL3042 warning: Avoid use of cache directory with pip. Use `pip install --no-cache-dir <package>`
python/examples/minimal_build/Dockerfile.ubuntu:38 DL3042 warning: Avoid use of cache directory with pip. Use `pip install --no-cache-dir <package>`