Fix bugs in api and add examples (#3353)

### What problem does this PR solve?

Fix bugs in api.
Add simple examples for api.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

docs/references/python_api_reference.md

@@ -1379,7 +1379,7 @@ assistant = assistant[0]
 session = assistant.create_session()    
 
 print("\n==================== Miss R =====================\n")
-print(assistant.get_prologue())
+print("Hello. What can I do for you?")
 
 while True:
     question = input("\n==================== User =====================\n> ")