fix bug

app.py

@@ -9,7 +9,7 @@ from tools.final_answer import FinalAnswerTool
 from Gradio_UI import GradioUI
 
 @tool
-def reliable_url(url)-> bool:
+def reliable_url(url:str)-> bool:
     """A tool that decides if a given url is a reliable source
     Args:
         url: the address of the webpage we want to know whether it is realible or not