Update app.py

app.py

@@ -133,7 +133,7 @@ class Reviewer:
 def main(api, review_format, paper_pdf, language):  
     start_time = time.time()
     if not api or not review_format or not paper_pdf:
-        return "请输入完整内容！"
+        comments =  "请输入完整内容！"
     # 判断PDF文件
     else:
         # 创建一个Reader对象