public function random_selector_string() {
        if ($this->question->qtype == 'random') {
            return $this->question->category .'/'. $this->question->questiontext;
        } else {
            return null;
        }
    }
public function random_selector_string() {
        if ($this->question->qtype == 'random') {
            return $this->question->category .'/'. $this->question->questiontext;
        } else {
            return null;
        }
    }
public function random_selector_string ( ) { if ( $ this -> question -> qtype == 'random' ) { return $ this -> question -> category . '/' . $ this -> question -> questiontext ; } else { return null ; } }
Used to determine which random questions pull sub questions from the same pools. Where pool means category and possibly
all the sub categories of that category.

@return null|string represents the pool of questions from which this question draws if it is random, or null if not.
Used to determine which random questions pull sub questions from the same pools . Where pool means category and possibly all the sub categories of that category .