environment variable method changed

app.py

@@ -53,7 +53,7 @@ class ChatWrapper:
                 os.environ["OPENAI_API_KEY"] = ""
 
             import openai
-            openai.api_key = os.environ["OPENAI_API_KEY"]
+            openai.api_key = os.environ.get("OPENAI_API_KEY")
             # Run chain and append input.
             output = chain({"question": inp, "chat_history": history})["answer"]
             history.append((inp, output))