Validates that items.attributes is a named list whose names are
truly unique after trimming whitespace and ignoring case, and that each
element is itself a list containing only strings, with at least two
truly unique strings (same trimming + case-insensitive rule).
Usage
items.attributes_validate(items.attributes)
Arguments
- items.attributes
A named list. Each element must be a list containing
only character scalars (strings). Each of those inner lists must contain
at least two truly unique strings after trimming and case-folding.
Value
A cleaned version of items.attributes with normalized names and
values. Errors are thrown if validation fails.