fix code snippet

docs/70-adding-memory/2-adding-memory.mdx

@@ -12,7 +12,7 @@ The answers for code blocks in this section are as follows:
 <summary>Answer</summary>
 <div>
 ```python
-config = {"configurable": {"thread_id": thread_id}}
+{"configurable": {"thread_id": thread_id}}
 ```
 </div>
 </details>