private function beautifyAuthorList($authors)
    {
        if ($authors === null) {
            return null;
        }

        $authors = \array_intersect_key($authors, \array_unique(\array_map('strtolower', $authors)));
        \usort($authors, 'strcasecmp');

        $mapped = [];
        foreach ($authors as $author) {
            $mapped[\strtolower($author)] = $author;
        }

        return $mapped;
    }
private function beautifyAuthorList($authors)
    {
        if ($authors === null) {
            return null;
        }

        $authors = \array_intersect_key($authors, \array_unique(\array_map('strtolower', $authors)));
        \usort($authors, 'strcasecmp');

        $mapped = [];
        foreach ($authors as $author) {
            $mapped[\strtolower($author)] = $author;
        }

        return $mapped;
    }
private function beautifyAuthorList ( $ authors ) { if ( $ authors === null ) { return null ; } $ authors = \ array_intersect_key ( $ authors , \ array_unique ( \ array_map ( 'strtolower' , $ authors ) ) ) ; \ usort ( $ authors , 'strcasecmp' ) ; $ mapped = [ ] ; foreach ( $ authors as $ author ) { $ mapped [ \ strtolower ( $ author ) ] = $ author ; } return $ mapped ; }
Ensure the list is case insensitively unique and that the authors are sorted.

@param string[]|null $authors The authors to work on.

@return string[] The filtered and sorted list.
Ensure the list is case insensitively unique and that the authors are sorted .