Fixed annotations example output_guardrails

Author: DanieleMorotti

examples/agent_patterns/output_guardrails.py

@@ -2,6 +2,7 @@
 
 import asyncio
 import json
+from typing import Union
 
 from pydantic import BaseModel, Field
 
@@ -31,7 +32,7 @@
 class MessageOutput(BaseModel):
     reasoning: str = Field(description="Thoughts on how to respond to the user's message")
     response: str = Field(description="The response to the user's message")
-    user_name: str | None = Field(description="The name of the user who sent the message, if known")
+    user_name: Union[str, None] = Field(description="The name of the user who sent the message, if known")
 
 
 @output_guardrail