Add return statement to get_papers function

app.py

@@ -109,6 +109,7 @@ def get_papers(
         arxiv_id = paper["externalIds"]["ArXiv"]
         url = f"https://huggingface.co/papers/{arxiv_id}"
         results += f"- [{paper_title}]({url})\n"
+    return results
 
 
 with gr.Blocks() as demo: