original_string: public function start_all_questions(question_variant_selection_strategy $variantstrategy = null,
              $timestamp = null, $userid = null) {
          if (is_null($variantstrategy)) {
              $variantstrategy = new question_variant_random_strategy();
          }
  
          foreach ($this->questionattempts as $qa) {
              $qa->start($this->preferredbehaviour, $qa->select_variant($variantstrategy), array(),
                      $timestamp, $userid);
              $this->observer->notify_attempt_modified($qa);
          }
      }
code: public function start_all_questions(question_variant_selection_strategy $variantstrategy = null,
              $timestamp = null, $userid = null) {
          if (is_null($variantstrategy)) {
              $variantstrategy = new question_variant_random_strategy();
          }
  
          foreach ($this->questionattempts as $qa) {
              $qa->start($this->preferredbehaviour, $qa->select_variant($variantstrategy), array(),
                      $timestamp, $userid);
              $this->observer->notify_attempt_modified($qa);
          }
      }
code_tokens: public function start_all_questions ( question_variant_selection_strategy $ variantstrategy = null , $ timestamp = null , $ userid = null ) { if ( is_null ( $ variantstrategy ) ) { $ variantstrategy = new question_variant_random_strategy ( ) ; } foreach ( $ this -> questionattempts as $ qa ) { $ qa -> start ( $ this -> preferredbehaviour , $ qa -> select_variant ( $ variantstrategy ) , array ( ) , $ timestamp , $ userid ) ; $ this -> observer -> notify_attempt_modified ( $ qa ) ; } }
docstring: Start the attempt at all questions that has been added to this usage.
  @param question_variant_selection_strategy how to pick which variant of each question to use.
  @param int $timestamp optional, the timstamp to record for this action. Defaults to now.
  @param int $userid optional, the user to attribute this action to. Defaults to the current user.
docstring_tokens: Start the attempt at all questions that has been added to this usage .