code: public function renderEmbed()
      {
          if(!$this->isValid($this->source)) {
              throw new InvalidSourceExtensionException();
          }
  
          return sprintf($this->embedDecorator, $this->width, $this->height, $this->source);
      }
docs: Renders the embed tag html with attached source
  
  @return string
  @throws Swf\Exception\InvalidSourceExtensionException