public function getEsiLayoutBlockNode($layout, $blockName) {
        // first try very specific by checking for action setEsiOptions inside block
        $blockNodes = $layout->getNode()->xpath(
            sprintf('//block[@name=\'%s\'][action[@method=\'setEsiOptions\']]',
                $blockName)
        );
        $blockNode = end($blockNodes);
        // fallback: only match name
        if ( ! ($blockNode instanceof Mage_Core_Model_Layout_Element)) {
            $blockNodes = $layout->getNode()->xpath(
                sprintf('//block[@name=\'%s\']', $blockName)
            );
            $blockNode = end($blockNodes);
        }
        return $blockNode;
    }