original_string: public function random_selector_string() {
          if ($this->question->qtype == 'random') {
              return $this->question->category .'/'. $this->question->questiontext;
          } else {
              return null;
          }
      }
code: public function random_selector_string() {
          if ($this->question->qtype == 'random') {
              return $this->question->category .'/'. $this->question->questiontext;
          } else {
              return null;
          }
      }
code_tokens: public function random_selector_string ( ) { if ( $ this -> question -> qtype == 'random' ) { return $ this -> question -> category . '/' . $ this -> question -> questiontext ; } else { return null ; } }
docstring: 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.
docstring_tokens: 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 .