small fix

app.py

@@ -2,6 +2,10 @@ import gradio as gr
 import os
 
 def process(tools, model, input_text, openai_key, serpapi_key):
+    if not openai_key:
+        openai_key = ""
+    if not serpapi_key:
+        serpapi_key = ""
     os.environ["OPENAI_API_KEY"] = openai_key
     os.environ["SERPAPI_API_KEY"] = serpapi_key
     from algos.PWS import PWS_Base