def get_thumbnails(self, size=None):
if not self.object_id:<EOL><INDENT>return []<EOL><DEDENT>url = self.build_url(<EOL>self._endpoints.get('<STR_LIT>').format(id=self.object_id))<EOL>params = {}<EOL>if size is not None:<EOL><INDENT>params['<STR_LIT>'] = size<EOL><DEDENT>response = self.con.get(url, params=params)<EOL>if not response:<EOL><INDENT>return []<EOL><DEDENT>data = response.json()<EOL>if not self.thumbnails or size is None:<EOL><INDENT>self.thumbnails = data<EOL><DEDENT>return data<EOL>
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