code: def get_thumbnails(self, size=None):
          
          if not self.object_id:
              return []
  
          url = self.build_url(
              self._endpoints.get('thumbnails').format(id=self.object_id))
  
          params = {}
          if size is not None:
              params['select'] = size
  
          response = self.con.get(url, params=params)
          if not response:
              return []
  
          data = response.json()
  
          if not self.thumbnails or size is None:
              self.thumbnails = data
  
          return data
docs: Returns this Item Thumbnails. Thumbnails are not supported on
          SharePoint Server 2016.
  
          :param size: request only the specified size: ej: "small",
           Custom 300x400 px: "c300x400", Crop: "c300x400_Crop"
          :return: Thumbnail Data
          :rtype: dict