def _update_engines(self, engines):
        """Update our engines dict and _ids from a dict of the form: {id:uuid}."""
        for k,v in engines.iteritems():
            eid = int(k)
            self._engines[eid] = v
            self._ids.append(eid)
        self._ids = sorted(self._ids)
        if sorted(self._engines.keys()) != range(len(self._engines)) and \
                        self._task_scheme == 'pure' and self._task_socket:
            self._stop_scheduling_tasks()
Update our engines dict and _ids from a dict of the form: {id:uuid}.