python3 ph-lesson-yaml-validator.py lesson.md

The script automatically detects the lesson type (either an original lesson or a translation) and selects the schema file accordingly:

• original-lesson-schema.yaml
• translated-lesson-schema.yaml

If the user prefers so, they can also specify another schema file with the argument --schemafile, followed by the file name, e.g.:

python3 ph-lesson-yaml-validator.py lesson.md --schemafile anotherschema.yaml

That's all. If you run the script and something is missing, you will see a message similar to this one:

abstract: Required field missing
doi: Required field missing