def get_cache_index_keys(self):
if not (self.id and self.tracking_id):<EOL><INDENT>raise NotImplementedError<EOL><DEDENT>return {<EOL>'<STR_LIT:id>': self.id,<EOL>'<STR_LIT>': self.tracking_id<EOL>}<EOL>
Return values available for retrieving records, but only for already existing records