def _unwrap_exception(self, content):
        e = error.unwrap_exception(content)
        # print e.traceback
        if e.engine_info:
            e_uuid = e.engine_info['engine_uuid']
            eid = self._engines[e_uuid]
            e.engine_info['engine_id'] = eid
        return e
unwrap exception, and remap engine_id to int.
dataset/ETHPy150Open ipython/ipython-py3k/IPython/parallel/client/client.py/Client._unwrap_exception