public function escapeHtmlAttribute($attribute)
    {
        if (!$this->escapeHtmlAttrHelper) {
            $this->escapeHtmlAttrHelper = $this->getView()->plugin('escapehtmlattr');
            if (!$this->escapeHtmlAttrHelper instanceof EscapeHtmlAttr) {
                throw new Exception\RuntimeException('Helper not loaded: escapeHtmlAttr');
            }
        }
        return $this->escapeHtmlAttrHelper->__invoke($attribute);
    }