Update get_weather function to return a formatted string instead of Weather object

Author: AnatoliB

samples-v2/openai_agents/function_app.py

@@ -138,11 +138,12 @@ class Weather:
     conditions: str
 
 @app.activity_trigger(input_name="city")
-async def get_weather(city: str) -> Weather:
+async def get_weather(city: str) -> str:
     """
     Get the weather for a given city.
     """
-    return Weather(city=city, temperature_range="14-20C", conditions="Sunny with wind.")
+    weather = Weather(city=city, temperature_range="14-20C", conditions="Sunny with wind.")
+    return f"Weather in {weather.city}: {weather.temperature_range}, {weather.conditions}"
 
 
 #region Implementation details