Magento – render() must be compatible with Magento\Backend\Block\Widget\Grid\Column\Renderer\RendererInterface::render(Magento\Framework\DataObject $row)

Fatal error: Declaration of
\ModuleName\Block\Adminhtml\ModuleName\Grid\Renderer\Image::render()
must be compatible with
Magento\Backend\Block\Widget\Grid\Column\Renderer\RendererInterface::render(Magento\Framework\DataObject
$row) in
C:\wamp\www\magento2\app\code\\ModuleName\Block\Adminhtml\ModuleName\Grid\Renderer\Image.php
on line 59

<?php
namespace <vendor-name>\ModuleName\Block\Adminhtml\ModuleName\Grid\Renderer;

use Magento\Backend\Block\Widget\Grid\Column\Renderer\AbstractRenderer;
use Magento\Framework\Object;
use Magento\Store\Model\StoreManagerInterface;

class Image extends AbstractRenderer
{
   private $_storeManager;
   /**
    * @param \Magento\Backend\Block\Context $context
    * @param array $data
    */

   public function __construct(\Magento\Backend\Block\Context $context, StoreManagerInterface $storemanager, array $data = [])
   {
       $this->_storeManager = $storemanager;
       parent::__construct($context, $data);
       $this->_authorization = $context->getAuthorization();
       echo "test";
   }
   /**
    * Renders grid column
    *
    * @param Object $row
    * @return  string
    */
   public function render(Object $row)
   {
       $mediaDirectory = $this->_storeManager->getStore()->getBaseUrl(
           \Magento\Framework\UrlInterface::URL_TYPE_MEDIA
       );
       $imageUrl = $mediaDirectory.'/FolderPathName'.$this->_getValue($row);


       return '<img src="'.$imageUrl.'" width="50"/>';
   }
}