大佬帮忙看看，执行命令 streamlit run web_ui.py --server.fileWatcherType none --server.port 8080，项目启动后，提问时报错：
2023-04-27 11:40:16.159 Uncaught app exception
Traceback (most recent call last):
File "/root/anaconda3/envs/ds/lib/python3.9/site-packages/streamlit/runtime/scriptrunner/script_runner.py", line 565, in _run_script
exec(code, module.__dict__)
File "/root/DocumentSearch/web_ui.py", line 36, in <module>
output_str, output_df = kl.search_result(input_str)
File "/root/DocumentSearch/demo.py", line 252, in search_result
search_table_info = pd.concat(
File "/root/anaconda3/envs/ds/lib/python3.9/site-packages/pandas/util/_decorators.py", line 331, in wrapper
return func(*args, **kwargs)
File "/root/anaconda3/envs/ds/lib/python3.9/site-packages/pandas/core/reshape/concat.py", line 368, in concat
op = _Concatenator(
File "/root/anaconda3/envs/ds/lib/python3.9/site-packages/pandas/core/reshape/concat.py", line 425, in __init__
raise ValueError("No objects to concatenate")
ValueError: No objects to concatenate
大佬帮忙看看，执行命令
streamlit run web_ui.py --server.fileWatcherType none --server.port 8080，项目启动后，提问时报错：