Update app.py

app.py

@@ -126,7 +126,7 @@ def end_session(req: gr.Request):
 def preprocess_image(image: Image.Image, 
                     prompt: str,
                     negative_prompt: str = "",
-                    style_name: "",
+                    style_name: str = "",
                     num_steps: int = 25,
                     guidance_scale: float = 5,
                     controlnet_conditioning_scale: float = 1.0,) -> Image.Image: