Whether level is a known value for a set of domain: a CEFR band (case-insensitive) for every domain, plus the explicit "none" sentinel for non-language domains only - a language set without a proficiency band is an authoring gap, not a category.
level
domain
"none"
Whether
levelis a known value for a set ofdomain: a CEFR band (case-insensitive) for every domain, plus the explicit"none"sentinel for non-language domains only - a language set without a proficiency band is an authoring gap, not a category.