code: public function formatMessage(
          /*# string */ $template,
          array $arguments = []
      )/*# : string */ {
          $this->stringize($arguments)->matchTemplate($template, $arguments);
          return vsprintf(
              $this->openTag .
              str_replace('%s', '<b>%s</b>', $template) .
              $this->closeTag,
              $arguments
          );
      }
docs: {@inheritDoc}