/**
  * @see Mage_Core_Block_Template::_toHtml()
  */
 protected function _toHtml()
 {
     if ($this->getOrders()->getSize() > 0) {
         return parent::_toHtml();
     }
     return '';
 }
 /**
  * Initialize default item renderer
  */
 protected function _construct()
 {
     parent::_construct();
     $this->addItemRender('default', 'checkout/cart_item_renderer', 'checkout/cart/item/default.phtml');
 }