Error out if API key is not given

app.py

@@ -5,6 +5,10 @@ import io
 
 # 修改 generate_image 函数以处理图像生成并保存为临时文件
 def generate_image(api_key, prompt, aspect_ratio, model, negative_prompt, seed):
+
+    if not api_key or not api_key.strip():
+        raise gr.Error("Please enter API key")
+
     response = requests.post(
         "https://api.stability.ai/v2beta/stable-image/generate/sd3",
         headers={