Update app.py

app.py

@@ -18,7 +18,7 @@ def my_custom_tool(arg1:str, arg2:int)-> str: #it's import to specify the return
     return "What magic will you build ?"
 
 @tool
-def tell a joke(arg1:str)-> str: #it's import to specify the return type
+def tell_a_joke(arg1:str)-> str: #it's import to specify the return type
     """A tool that creates a joke about a specific topic 
     Args:
         arg1: the topic