[问题/Issue] 章节8：运行chapter8/09_Memory_Types_Deep_Dive.py的demonstrate_episodic_memory方法检索不出记忆数据

### 1. 遇到问题的章节 / Affected Chapter chapter8/09_Memory_Types_Deep_Dive.py ### 2. 问题类型 / Issue Type 代码错误 / Code Error ### 3. 具体问题描述 / Problem Description - demonstrate_episodic_memory方法运行时出现：**WARNING:hello_agents.memory.manager:检索 episodic 记忆时出错: 'str' object has no attribute 'get'** <img width="2132" height="488" alt="Image" src="https://github.com/user-attachments/assets/a7a7c5a9-f95d-47c5-bf86-16c3abb53253" /> - episodic.py 的 retrieve 方法 <img width="1878" height="916" alt="Image" src="https://github.com/user-attachments/assets/137ed3d7-da42-4012-aaa9-8a9b1345293f" /> - 使用的版本是`pip install "hello-agents[all]==0.2.0"` ### 4. 问题重现材料 / Reproduction Materials 代码地址：https://github.com/datawhalechina/hello-agents/blob/main/code/chapter8/09_Memory_Types_Deep_Dive.py 原测试数据的context为字符串类型，导致运行报错 <img width="1328" height="1206" alt="Image" src="https://github.com/user-attachments/assets/88d2b93b-ac4a-4333-b149-ab5222d3c159" /> ### 5. 补充信息 / Additional Information 将context字段格式修改后可以解决 ```python learning_session = [ { "content": "开始学习Python机器学习", "context": {"step": "学习开始"}, "location": "家里书房", "mood": "专注", "importance": 0.7 }, ....] ``` ### 确认事项 / Verification - [x] 我已阅读过相关章节的文档 / I have read the relevant chapter documentation - [x] 我已搜索过现有的Issues,确认此问题未被报告 / I have searched existing Issues and confirmed this hasn't been reported - [ ] 我已尝试过基本的故障排除(如重启、重新安装依赖等) / I have tried basic troubleshooting (restart, reinstall dependencies, etc.)