original_string: public function set_observer($observer) {
          $this->observer = $observer;
          foreach ($this->questionattempts as $qa) {
              $qa->set_observer($observer);
          }
      }
code: public function set_observer($observer) {
          $this->observer = $observer;
          foreach ($this->questionattempts as $qa) {
              $qa->set_observer($observer);
          }
      }
code_tokens: public function set_observer ( $ observer ) { $ this -> observer = $ observer ; foreach ( $ this -> questionattempts as $ qa ) { $ qa -> set_observer ( $ observer ) ; } }
docstring: You should almost certainly not call this method from your code. It is for
  internal use only.
  @param question_usage_observer that should be used to tracking changes made to this usage.
docstring_tokens: You should almost certainly not call this method from your code . It is for internal use only .