Update app.py

app.py

@@ -28,6 +28,8 @@ from assistants import (
     extract_content_values,
 )
 
+lock = threading.Lock()
+
 def chat(message, history, openai_api_key):
     if not openai_api_key:
         raise gr.Error("OpenAI API Key is required (see additional inputs below).")