code: public function renderDynamic($statements)
      {
          if (!empty($this->cacheStack)) {
              $n = count($this->dynamicPlaceholders);
              $placeholder = "<![CDATA[YII-DYNAMIC-$n]]>";
              $this->addDynamicPlaceholder($placeholder, $statements);
  
              return $placeholder;
          }
  
          return $this->evaluateDynamicContent($statements);
      }
docs: Renders dynamic content returned by the given PHP statements.
  This method is mainly used together with content caching (fragment caching and page caching)
  when some portions of the content (called *dynamic content*) should not be cached.
  The dynamic content must be returned by some PHP statements.
  @param string $statements the PHP statements for generating the dynamic content.
  @return string the placeholder of the dynamic content, or the dynamic content if there is no
  active content cache currently.