return type hint added for multiply tool

app.py

@@ -34,7 +34,7 @@ def get_current_time_in_timezone(timezone: str) -> str:
         return f"Error fetching time for timezone '{timezone}': {str(e)}"
 
 @tool
-def multiply(a: int, b: int):
+def multiply(a: int, b: int) -> int:
     """ A tool that multiply two integer numbers and returns the result.
     Args:
         a: first integer number