docs: private void validate(Concept concept) {
          validateParam(concept, TYPE, Thing.class, Thing::type);
          validateParam(concept, SUPER_CONCEPT, SchemaConcept.class, SchemaConcept::sup);
          validateParam(concept, LABEL, SchemaConcept.class, SchemaConcept::label);
          validateParam(concept, ID, Concept.class, Concept::id);
          validateParam(concept, VALUE, Attribute.class, Attribute::value);
          validateParam(concept, DATA_TYPE, AttributeType.class, AttributeType::dataType);
          validateParam(concept, WHEN, Rule.class, Rule::when);
          validateParam(concept, THEN, Rule.class, Rule::then);
      }