code: def getThumbnailForItem(self, itemId, fileName, filePath):
          
          admin = None
          item = None
  
          try:
              admin = arcrest.manageorg.Administration(securityHandler=self._securityHandler)
              item = admin.content.getItem(itemId = itemId)
              return item.saveThumbnail(fileName=fileName,filePath=filePath)
          except:
              line, filename, synerror = trace()
              raise common.ArcRestHelperError({
                          "function": "getThumbnailForItem",
                          "line": line,
                          "filename":  filename,
                          "synerror": synerror,
                                          }
                                          )
          finally:
              admin = None
              item = None
              del admin
              del item
              gc.collect()
docs: Gets an item's thumbnail and saves it to disk.
          
          Args:
              itemId (str): The item's ID.
              fileName (str): The name of the output image.
              fileName (str): The directory on disk where to save the thumbnail.
          Returns:
              dict: The result from :py:func:`arcrest.manageorg._content.UserItem.saveThumbnail`