def _unwrap_exception(self, content):
e = error.unwrap_exception(content)<EOL>if e.engine_info:<EOL><INDENT>e_uuid = e.engine_info['<STR_LIT>']<EOL>eid = self._engines[e_uuid]<EOL>e.engine_info['<STR_LIT>'] = eid<EOL><DEDENT>return e<EOL>
unwrap exception, and remap engine_id to int.