original_string: public function restart_preview_button() {
          global $OUTPUT;
          if ($this->is_preview() && $this->is_preview_user()) {
              return $OUTPUT->single_button(new moodle_url(
                      $this->start_attempt_url(), array('forcenew' => true)),
                      get_string('startnewpreview', 'quiz'));
          } else {
              return '';
          }
      }
code: public function restart_preview_button() {
          global $OUTPUT;
          if ($this->is_preview() && $this->is_preview_user()) {
              return $OUTPUT->single_button(new moodle_url(
                      $this->start_attempt_url(), array('forcenew' => true)),
                      get_string('startnewpreview', 'quiz'));
          } else {
              return '';
          }
      }
code_tokens: public function restart_preview_button ( ) { global $ OUTPUT ; if ( $ this -> is_preview ( ) && $ this -> is_preview_user ( ) ) { return $ OUTPUT -> single_button ( new moodle_url ( $ this -> start_attempt_url ( ) , array ( 'forcenew' => true ) ) , get_string ( 'startnewpreview' , 'quiz' ) ) ; } else { return '' ; } }
docstring: Print the HTML for the start new preview button, if the current user
  is allowed to see one.
docstring_tokens: Print the HTML for the start new preview button if the current user is allowed to see one .