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 generate_image_prompt(prompt:str)->
+def generate_image_prompt(prompt:str)-> str:
     """Generates an image based on the provided prompt using the image generation tool.
         Args:
             prompt: A textual description for the image to be generated.