Collects experience information from all external brains in environment at current step.
        :return: a dictionary of BrainInfo objects.

def _get_state(self, output: UnityRLOutput) -> (AllBrainInfo, bool):
        """
        Collects experience information from all external brains in environment at current step.
        :return: a dictionary of BrainInfo objects.
        """
        _data = {}
        global_done = output.global_done
        for brain_name in output.agentInfos:
            agent_info_list = output.agentInfos[brain_name].value
            _data[brain_name] = BrainInfo.from_agent_proto(agent_info_list,
                                                           self.brains[brain_name])
        return _data, global_done